Jere Lull wrote:

ONLY if you're only looking at the filter.

Did you somehow miss this?

The element cannot possibly know what mechanism is used to
establish fluid flow through the filter.

Did I write filter housing?


Rick

Changing the oil every 100 hours isn't much of a chore. My engine
only holds 2 gallons. 110VAC polishing systems would be a pain
when at ancor or under sail. Can't justify running the genset for
hours on end. A nice 12VDC pump drawing just a few amps
can be supported easier on PV and wind.\\

Doug
s/v Callista

"Rick" wrote in message
.net...
Doug Dotson wrote:

Actually, we are talking about permanently installed polishing systems
that run for extended periods of time. In general, they run the entire
time
the engine iss running and also when the boat is sitting at anchor or at
a
dock they run for several hours per week.

OK, in that case I would look very closely at the Alfa Laval
unit. It is very small, 110VAC low power. No filter beats a
centrifuge for use like that.

If I really wanted to do it right I would put one on the
lube oil as well.

Rick

Changing the oil every 100 hours isn't much of a chore. My engine
only holds 2 gallons. 110VAC polishing systems would be a pain
when at ancor or under sail. Can't justify running the genset for
hours on end. A nice 12VDC pump drawing just a few amps
can be supported easier on PV and wind.\\

Doug
s/v Callista

"Rick" wrote in message
.net...
Doug Dotson wrote:

Actually, we are talking about permanently installed polishing systems
that run for extended periods of time. In general, they run the entire
time
the engine iss running and also when the boat is sitting at anchor or at
a
dock they run for several hours per week.

OK, in that case I would look very closely at the Alfa Laval
unit. It is very small, 110VAC low power. No filter beats a
centrifuge for use like that.

If I really wanted to do it right I would put one on the
lube oil as well.

Rick

In article ,
(Steven Shelikoff) wrote:

On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote:

In article ,
Rick wrote:

The element cannot possibly know what mechanism is used to
establish fluid flow through the filter. The only thing the
filter sees is rate of flow and as it clogs, differential.
Anyone who claims otherwise is ignoring some other factor or
talking BS.

ONLY if you're only looking at the filter.

We are only looking at the filter, not taking into account the casing,
plumbing, etc.

Steve

I believe that the case is a pretty major component to ignore in a
polishing system. A case designed for partial vacuum may not properly
handle whatever pressure the pump can deliver. If the company says "only
suction", I suspect it wasn't designed for pressure.

Getting back to the filter alone: Since I believe most pumps can "push"
better than they can "pull", we should also consider the maximum
differential the filter can handle before it tears or otherwise breaks
down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can
these pumps deliver?

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

In article ,
(Steven Shelikoff) wrote:

On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote:

In article ,
Rick wrote:

The element cannot possibly know what mechanism is used to
establish fluid flow through the filter. The only thing the
filter sees is rate of flow and as it clogs, differential.
Anyone who claims otherwise is ignoring some other factor or
talking BS.

ONLY if you're only looking at the filter.

We are only looking at the filter, not taking into account the casing,
plumbing, etc.

Steve

I believe that the case is a pretty major component to ignore in a
polishing system. A case designed for partial vacuum may not properly
handle whatever pressure the pump can deliver. If the company says "only
suction", I suspect it wasn't designed for pressure.

Getting back to the filter alone: Since I believe most pumps can "push"
better than they can "pull", we should also consider the maximum
differential the filter can handle before it tears or otherwise breaks
down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can
these pumps deliver?

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

Jere Lull wrote:

I believe that the case is a pretty major component to ignore in a
polishing system.

You must have missed quite a few posts. The discussion you
entered was about the mechanism for moving a fluid across
the filter element. We were not discussing the entire filter
assembly or its place in the system.

Rick

Jere Lull wrote:

I believe that the case is a pretty major component to ignore in a
polishing system.

You must have missed quite a few posts. The discussion you
entered was about the mechanism for moving a fluid across
the filter element. We were not discussing the entire filter
assembly or its place in the system.

Rick

In article . net,
Rick wrote:

Jere Lull wrote:

I believe that the case is a pretty major component to ignore in a
polishing system.

You must have missed quite a few posts. The discussion you
entered was about the mechanism for moving a fluid across
the filter element. We were not discussing the entire filter
assembly or its place in the system.

Rick

I *had* read the whole thread, and felt that it had lost its way,
talking theoretically about just the filter when a real-life system
includes quite a bit more.

I didn't even mention the 4 or more extra joints that would be probable
problem points if pressurized. The time we got a plugged tank pickup, I
found out that one or more of our joints leaked air into the system.
They don't give us any problem under normal operation. I strongly
suspect that if I pressurized the system, that/those joint(s) would drip
fuel very slowly. While not a safety problem with diesel, it's a mess I
want to avoid. (The first mate is strongly affected by the smell. If she
ain't happy, ain't no one happy!) They're all torqued to spec, so I'd
have to exceed recommended torque(s) to stop the leak(s).

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

In article . net,
Rick wrote:

Jere Lull wrote:

I believe that the case is a pretty major component to ignore in a
polishing system.

You must have missed quite a few posts. The discussion you
entered was about the mechanism for moving a fluid across
the filter element. We were not discussing the entire filter
assembly or its place in the system.

Rick

I *had* read the whole thread, and felt that it had lost its way,
talking theoretically about just the filter when a real-life system
includes quite a bit more.

I didn't even mention the 4 or more extra joints that would be probable
problem points if pressurized. The time we got a plugged tank pickup, I
found out that one or more of our joints leaked air into the system.
They don't give us any problem under normal operation. I strongly
suspect that if I pressurized the system, that/those joint(s) would drip
fuel very slowly. While not a safety problem with diesel, it's a mess I
want to avoid. (The first mate is strongly affected by the smell. If she
ain't happy, ain't no one happy!) They're all torqued to spec, so I'd
have to exceed recommended torque(s) to stop the leak(s).

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

On Fri, 09 Jan 2004 14:47:50 GMT, Rich Hampel
wrote:

Another good reason NOT to pull vacuum on fuels and other volitile
liquids is that if the vacuum exceeds the vapor pressure of the fluid
the liquid with boil (flash) or you will separate out the lighter
fractions (lighter weight hydrocarbons). If youve ever had a gasoline
that had 'vapor-lock' problems you'll understand this phenomenom. I
dont have by me at this time a listing of the vapor pressure range of

That's pretty much self regulating in this case. I.e., if you had a
pump that was strong enough to create a vapor lock due to a very high
vacuum, it would stop pumping and the vacuum would decrease and the
vapor lock would be cured.

But then again, if you had so much of a pressure difference on most of
the filters we're talking about here that the fuel boils due to the
vacuum of being drawn through the filter, it's time to change the
element anyway. Either that or the pump is too strong and will destroy
the filter.

Steve