Hello,

I am trying to finish my electric bilge pump for my kayak. At first, I was
thinking electronic valves, but I found that they will not do the job for
me. They are too big and expensive, among other things.

So, I am asking for your help - I need one of these two things (either, not
both):

1.) Either 3/4 inch, 1 inch, 1 1/8 inch (ideal) check valve. The check valve
must be small, semi cheap, seal perfectly when closed (not ONE drip), and be
able to open with the slightest pressure (just a dribble of water pushing up
from the pump)

[or]

2.) A 3/4 inch or 1 1/8 inch 12 volt electric water pump (about 800-1000
gallons per hour) that needs to be pretty light. The pump MUST not let ONE
drip of water back through it when off. This means it will act as a check
valve. I had bought one at West Marine, where they told me it didn't let any
water back, but it does. :-(

Thanks for your help!

Karl

Karl Timmermann wrote:
I am trying to finish my electric bilge pump for my kayak.

must be small, semi cheap, seal perfectly when closed (not ONE drip)

Why must it be absolutely perfect? Won't you be letting a single drop
of water in past the pilot? Won't your bilge pump handle any water
that leaks into the boat?

What did you find at McMaster-Carr that you didn't like?

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com

Karl Timmermann wrote:

I am trying to finish my electric bilge pump for my kayak.

A Google search will turn up a herd of manufacturers of plastic check
valves and nearly all of them have a simple little diaphragm check valve
that will suit your needs.

If you want to prevent the water between the pump and the thru-hull from
draining back into the bilge you will need to mount the check valve
directly on the pump discharge fitting.

This isn't an electronics problem, it is a simple application of an
easily obtained mechanical component installed in the correct place.

Rick

"Karl Timmermann" wrote in message
...

2.) A 3/4 inch or 1 1/8 inch 12 volt electric water pump (about 800-1000
gallons per hour) that needs to be pretty light. The pump MUST not let ONE
drip of water back through it when off. This means it will act as a check
valve. I had bought one at West Marine, where they told me it didn't let
any
water back, but it does. :-(

If the thing doesn't operate the way they said it's supposed to, then
it's a defective unit and needs to be replaced by the store. It's called
implied merchantability.

Good Luck!
Rich

"Karl Timmermann" wrote in message
...
Hello,

I am trying to finish my electric bilge pump for my kayak. [...]

2.) A 3/4 inch or 1 1/8 inch 12 volt electric water pump (about 800-1000
gallons per hour) that needs to be pretty light.

That amounts to 2 pints (a quart) a second! Are you sure your
hand pump can do that? Sounds a bit much to this land-lubber.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

Don't know what I'm talking about here but I once saw a diagram where you
create a "loop" in your discharge hose so that it is above the water line.
At the top of the loop you have a "fitting" that allows air to enter if
there is a vacuum in the hose but seals when there is pressure in the hose.
Someone else here must know what I'm referring to? Would this do the job?
BruceM


"Graham W" wrote in message
...

"Karl Timmermann" wrote in message
...
Hello,

I am trying to finish my electric bilge pump for my kayak. [...]

2.) A 3/4 inch or 1 1/8 inch 12 volt electric water pump (about 800-1000
gallons per hour) that needs to be pretty light.

That amounts to 2 pints (a quart) a second! Are you sure your
hand pump can do that? Sounds a bit much to this land-lubber.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

You are referring to an "anti siphon valve" or sometimes called a "snifter"
valve. These valves are reliable. but rely on pressure to seal, if the
pressure is low, the seal is not tight - with the potential for a "drip". I
also don't see the need for absolute perfection in the seal?

Mick
"BruceM" wrote in message
...
Don't know what I'm talking about here but I once saw a diagram where you
create a "loop" in your discharge hose so that it is above the water line.
At the top of the loop you have a "fitting" that allows air to enter if
there is a vacuum in the hose but seals when there is pressure in the
hose.
Someone else here must know what I'm referring to? Would this do the job?
BruceM


"Graham W" wrote in message
...

"Karl Timmermann" wrote in message
...
Hello,

I am trying to finish my electric bilge pump for my kayak. [...]

2.) A 3/4 inch or 1 1/8 inch 12 volt electric water pump (about
800-1000
gallons per hour) that needs to be pretty light.

That amounts to 2 pints (a quart) a second! Are you sure your
hand pump can do that? Sounds a bit much to this land-lubber.


--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.