World's most complicated bilge system revisited
 

Larry, Brian, and Ian, you'll all get a kick out of this puzzler.

They finally got the water turned on in the marina so I could wash the
shipyard filth off and out of our boat. I also decided to watch the
bilge system in action.

I DOESN'T WORK!

I repeated the hand tests just to be sure and it functions exactly as
intended. Pick up a top float switch and it runs until the switch is
dropped. Fine for checking that the pump is running.

Pick up a bottom switch. Nothing happens. Hold the bottom switch up
and lift the top switch. Pump starts. Drop the top switch and it runs
till you drop the bottom switch.

When you fill it slowly with water however, it acts like the bottom
switches aren't even there. It starts when a top switch goes ON and
stops when the top switch goes down a bit.

Another strange thing: It doesn't go into the endless cycle that the
pumps did when I tested them with the same hose length and simulated
sump size. There is much less backflow.

Here's my theory on that: In my basement test, I ran the hose out the
window and up the hill. In the boat, it has a long gentle rise along
the middle portions ending in a high loop. I had the test set up
arranged so the pump didn't suck air. In the boat, the switches are
set to get the bilge as dry as possible. The water is moving pretty
fast through the hose. The inertia, the siphoning in the high loop,
and the pump still pushing some even though cavitating, all conspire
to clear the line. It looks as though there is about half as much back
flow in real life as in the test rig which matched the calculated
volume.

I'm stumped though about the current behavior. I confirmed that the
ball in the lower switches is rolled back when the pumping starts. You
can look at the circuit again he

http://home.maine.rr.com/rlma/BilgeCircuit.jpg

But I don't think it's the logic. I have a functioning bilge system
that doesn't feedback cycle but I'm left with four inches of water to
pump out by hand or by manipulation of the float switches.

All this goes to show why they test rockets before sending anyone up
in them.

--

Roger Long

"Roger Long" wrote in
:

http://home.maine.rr.com/rlma/BilgeCircuit.jpg

WHOA! There's no DC power to the low float switch! So, the low float
switch cannot power up the relay coils! If you close the high switch, IT
delivers power to the lower float switch, and because it is closed already,
it powers up the relay. Now that the relay has power it will hold power on
itself through the lower float switch until that switch opens. When that
switch closes again, again it has no power until the high float switch
closes.

Now, it's simple to fix. MOVE the lower float switch connection on the
high float switch from the right side of it to the left side, the side
that goes to the fuses. Voila! The power's always on the lower float
switch, now and it will always key the relays. Do it on both pumps.

Problem solved....next problem....

By the way, I fixed a Russian TV set by remote control a few weeks ago. It
was sitting on Sergei's desk on Sahkalin Island in the Sea of Japan. He
emailed me a PDF file of the schematic so I had it in front of me. We used
the color cams so I could direct the connection of his DVM to the circuit I
wanted to test. Found a shorted capacitor in the horizontal sweep circuit.
There's now a working TV being watched by two kids in Sahkalin Island,
Russia, because of me....way cool...(c;

--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.

"Roger Long" wrote in
:

http://home.maine.rr.com/rlma/BilgeCircuit.jpg

Can you explain to me why you are using these relays on the lower switches?
Why not just parallel the lower switches with the upper switches and be
done with it? The problem with using an electrical switch with no or
little current through it, like this relay nonsense, is that the contacts
don't get cleaned with a good arc because the tiny current the relay uses
doesn't produce a cleaning arc. The 2-3A motor hardly fulfills this
requirement.

I don't like the rolling ball switches. Enclosed mercury switches, like
the Rule float switch uses, is self-healing and very reliable if you keep
large trash from holding it ON by getting under it. A simple screen
dropped over it fixes that problem. The Rule float switches in Lionheart
control the pumping overboard of all sink, shower, sump garbage that goes
down the drains. They work just fine! Maybe it's the dish detergent that
keeps 'em clean. It cleans the bilge of oil. "Dawn moves grease out of
your way"....even in bilges!

--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.

Wild guess: the lower float cuts off again with enough upthrust on it,
for which it was not intended.

Brian Whatcott

On Mon, 13 Jun 2005 23:35:39 GMT, "Roger Long"
wrote:

Larry, Brian, and Ian, you'll all get a kick out of this puzzler.

They finally got the water turned on in the marina so I could wash the
shipyard filth off and out of our boat. I also decided to watch the
bilge system in action.

I DOESN'T WORK!

I repeated the hand tests just to be sure and it functions exactly as
intended. Pick up a top float switch and it runs until the switch is
dropped. Fine for checking that the pump is running.

Pick up a bottom switch. Nothing happens. Hold the bottom switch up
and lift the top switch. Pump starts. Drop the top switch and it runs
till you drop the bottom switch.

When you fill it slowly with water however, it acts like the bottom
switches aren't even there. It starts when a top switch goes ON and
stops when the top switch goes down a bit.

Another strange thing: It doesn't go into the endless cycle that the
pumps did when I tested them with the same hose length and simulated
sump size. There is much less backflow.

Here's my theory on that: In my basement test, I ran the hose out the
window and up the hill. In the boat, it has a long gentle rise along
the middle portions ending in a high loop. I had the test set up
arranged so the pump didn't suck air. In the boat, the switches are
set to get the bilge as dry as possible. The water is moving pretty
fast through the hose. The inertia, the siphoning in the high loop,
and the pump still pushing some even though cavitating, all conspire
to clear the line. It looks as though there is about half as much back
flow in real life as in the test rig which matched the calculated
volume.

I'm stumped though about the current behavior. I confirmed that the
ball in the lower switches is rolled back when the pumping starts. You
can look at the circuit again he

http://home.maine.rr.com/rlma/BilgeCircuit.jpg

But I don't think it's the logic. I have a functioning bilge system
that doesn't feedback cycle but I'm left with four inches of water to
pump out by hand or by manipulation of the float switches.

All this goes to show why they test rockets before sending anyone up
in them.

"Larry W4CSC" wrote in message
...
Problem solved....next problem....

But, that doesn't explain why it works exactly as intended when
manipulated by hand. It acts as if it is rate dependent. Move the
switches quickly and it works, move them slowly and it doesn't.

Since the system turns out not to go into endless cycle mode, I may
just go back to simple parallel switches. I want to understand the
lack of cycling better though and be sure it isn't something dependent
on the lines and strainers being new, etc.

I agree about the relays and wouldn't use this system in a boat where
it cycled a lot like a leaky wooden boat. In this case however, relay
action will be pretty infrequent. I still want to get it working
though. As they say, the journey is the destination.


By the way, I fixed a Russian TV set by remote control a few weeks
ago.

That's too cool. Great world we live in. I hear doctors are going to
start performing operations over the net with robot manipulators.
They already use them in the operating room. Once you are using the
monitor and the joysticks anyway, it doesn't matter how long the wire
is.

--

Roger Long

"Larry W4CSC" wrote in message
...
Can you explain to me why you are using these relays on the lower
switches?
Why not just parallel the lower switches with the upper switches and
be
done with it?

I guess you weren't in on the discussions leading up to this design.

Testing an earlier version of my dual pump rig with it's long dual
hoses in a plastic tub of approximately the same surface area of my
bilge sump, I discovered that the backflow through the bilge lines
with the pumps quit would raise the sump level slightly more than the
activation range of any bilge switch I could find. I didn't want to
relocate the bilge lines to shorten them or use checkvalves.

The purpose of this is to simulate a float switch with a four inch
activation range so there is no possibility of backflow setting up an
endless pumping cycle. The system has turned out to have other
advantages. The lower switches can't turn the pumps on by themselves.
When the top switches go on just once, they trip the relay and the
system then pumps all the way down. This provides built in protection
from the pumps "chirping" in a seaway due to sloshing. If I want to
pump the bilge down after it has filled enough for the lower switches
to activate but not wait for it to reach full pump activation depth, I
can just give a top switch a flick and then forget it. It will pump
full down without holding the switch up.

It turns out to be maybe unnecessary because the backflow is less than
in my test or calculations. Still, it was fun working the system out
and putting it together.

--

Roger Long

"Roger Long" wrote in
:

But, that doesn't explain why it works exactly as intended when
manipulated by hand.

What you've hooked up is a "latching relay". Once the high switch is just
momentarily activated, even for a few milliseconds, the power it provides
closes the relay contacts, which THEN provide the power to keep the power
flowing in the absense of contact in the high switch. It "latches" to ON
and will stay on as long as the low switch is closed. If the low switch
opens just momentarily (the boat rolls?), the relay drops out and now there
is no power to the low switch because the high switch is open so the relay
cannot be re-energized until the high switch turns on. This circuit would
be great if you only wanted the bilge pump to run after the water got "so
high" (where the high switch activates), but kept the bilge pump running to
dry the bilge to the point the low switch opened...(c;

Just move the wire powering the low switch from the side the schematic
shows on the high switch to the other side of the high switch and your
problem is solved....no more latching and lockout.

Beautiful drawing, by the way. What I'd expect from such a fine marine
architect.

--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.

"Roger Long" wrote in
:

It turns out to be maybe unnecessary because the backflow is less than
in my test or calculations. Still, it was fun working the system out
and putting it together.



Backflow is inevitable in such cheap impeller pumps we put in boats.
Backflow is also important in CLEARING the pump of trash it has sucked into
its intake grate. A good splash of backflow blows the trash out of the
pump so the next time it comes in it will start cleared until the trash
gets sucked into it again. Therefore, I don't consider backflow to be
"bad". The bilge isn't going to be dry with these pumps, anyways.

When Geoffrey bought Lionheart, an Amel Sharki 41 (39 if you're talking to
our marina people), I was amazed that all the sink drains, shower drain and
bilge water didn't simply make an awful smelly mess in the bilge. The
original French pump Amel installed was a positive-displacement diaphram
pump, quite large, but manually operated by the breaker. The former owner
had no concept of "maintenance" on such as DC motors or pumps, so it was
just worn in two from lack of a few drops of oil. The armature was against
the stator dragging every time it came on. It was replaced by the biggest
Rule, some bogus rating of 4000 gph, which was placed way down in the keel,
about 5 feet under the galley sole with a Rule float switch. Everything in
the boat dumps into this deep space whos sides are very steep, indeed. A
pipe with a ball valve on the end so you can secure it, runs forward to the
shower/sink which dump unceremoniously into the bilge under the false deck
in the head. The shower really has no drain at all, it just falls through
the holes in the wooden deck into the forward bilge, forward of the 2nd
watertight bulkhead, the forward bulkhead of the main cabin. You secure
the hatch with a mahogany (of course) bar and turn off the drain valve to
prevent flooding.

The arrangement works quite well. Once at sea, after dishwashing, I get
out the old pump handle to the manual monster under the steps and use it to
pump out whatever solids have collected. It has a very nice foot piece at
the bilge bottom that really sucks it dry. The big Rule sucks out most of
it.



--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.

"Larry W4CSC" wrote

This circuit would
be great if you only wanted the bilge pump to run after the water
got "so
high" (where the high switch activates), but kept the bilge pump
running to
dry the bilge to the point the low switch opened...(c;


That is a succinct statement of the exact design objective.

--

Roger Long

"Roger Long" wrote in
:

That is a succinct statement of the exact design objective.

--

Roger Long


Aha...now I see. To adjust the limits, just move the floatswitch location
up or down....easy.

--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.

Here's another potential solution:
There is such a thing as a relay with a delay. They are available
occasionally throughC&H Surplus at bargan prices. I believe that I
have seen them at McMaster-Carr also. Using a capacitor and a resistor
you could easily make one. Just do away with the lower switch, and use
the duration on the delay to pump bilge water down low enough that the
backwash wont re-trigger the remaining higher switch.
Good luck...

On Mon, 13 Jun 2005 23:35:39 GMT, "Roger Long"
wrote:

Larry, Brian, and Ian, you'll all get a kick out of this puzzler.

They finally got the water turned on in the marina so I could wash the
shipyard filth off and out of our boat. I also decided to watch the
bilge system in action.

I DOESN'T WORK!

I repeated the hand tests just to be sure and it functions exactly as
intended. Pick up a top float switch and it runs until the switch is
dropped. Fine for checking that the pump is running.

Pick up a bottom switch. Nothing happens. Hold the bottom switch up
and lift the top switch. Pump starts. Drop the top switch and it runs
till you drop the bottom switch.

When you fill it slowly with water however, it acts like the bottom
switches aren't even there. It starts when a top switch goes ON and
stops when the top switch goes down a bit.

Another strange thing: It doesn't go into the endless cycle that the
pumps did when I tested them with the same hose length and simulated
sump size. There is much less backflow.

Here's my theory on that: In my basement test, I ran the hose out the
window and up the hill. In the boat, it has a long gentle rise along
the middle portions ending in a high loop. I had the test set up
arranged so the pump didn't suck air. In the boat, the switches are
set to get the bilge as dry as possible. The water is moving pretty
fast through the hose. The inertia, the siphoning in the high loop,
and the pump still pushing some even though cavitating, all conspire
to clear the line. It looks as though there is about half as much back
flow in real life as in the test rig which matched the calculated
volume.

I'm stumped though about the current behavior. I confirmed that the
ball in the lower switches is rolled back when the pumping starts. You
can look at the circuit again he

http://home.maine.rr.com/rlma/BilgeCircuit.jpg

But I don't think it's the logic. I have a functioning bilge system
that doesn't feedback cycle but I'm left with four inches of water to
pump out by hand or by manipulation of the float switches.

All this goes to show why they test rockets before sending anyone up
in them.