The smaller the retention size of the filter, and so arranged for
drainage so as not to collect free water inside the filter (core) will
coalesce the emulsion and effect separation into free water and cleaned
oil .... just need a proper sump volume at the bottom of the filter
bowl. The mathematical enhancement of repeated passes (tank turnovers)
through a recirculating filter will more than adequately take care of
'emulsions'.


The use of a centrifuge on the small volume boat tankage .... borders
on ludicrous. Centrifuges are extreme high maintenance rotating and
power consuming equipment and do NOT effect total removal/separation of
emulsions. If you have enough power to run a centrifuge, then I
suggest that you rip out the fossil fuel engine and simply replace with
an electric motor for propulsion. Do you also use a nephalometer to
arrive at when the centrifugation is complete?
As an aside .... a water emulsion will enhance the combustion
efficiency by increase of the apparent cetane number of the fuel, or
the octane number in a gasoline engine. Its the FREE water thats the
'problem' as simply 'slugs' of free water simply do not burn.



In article k.net,
Rick wrote:

Steven Shelikoff wrote:

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

The difference is that if the pump suction pulls water and
fuel directly from the tank it will do an excellent job of
mixing it up to form an emulsion that will not filter out
very effectively.

The path should be, a basket strainer to catch the chunks, a
separarator/filter to eliminate the bulk of the water and
the smaller suspended particles, the pump, then the finer
stages of filtration.

This is all assuming you don't have access to a centrifuge
which is really the best way to handle the process.

Rick

The smaller the retention size of the filter, and so arranged for
drainage so as not to collect free water inside the filter (core) will
coalesce the emulsion and effect separation into free water and cleaned
oil .... just need a proper sump volume at the bottom of the filter
bowl. The mathematical enhancement of repeated passes (tank turnovers)
through a recirculating filter will more than adequately take care of
'emulsions'.


The use of a centrifuge on the small volume boat tankage .... borders
on ludicrous. Centrifuges are extreme high maintenance rotating and
power consuming equipment and do NOT effect total removal/separation of
emulsions. If you have enough power to run a centrifuge, then I
suggest that you rip out the fossil fuel engine and simply replace with
an electric motor for propulsion. Do you also use a nephalometer to
arrive at when the centrifugation is complete?
As an aside .... a water emulsion will enhance the combustion
efficiency by increase of the apparent cetane number of the fuel, or
the octane number in a gasoline engine. Its the FREE water thats the
'problem' as simply 'slugs' of free water simply do not burn.



In article k.net,
Rick wrote:

Steven Shelikoff wrote:

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

The difference is that if the pump suction pulls water and
fuel directly from the tank it will do an excellent job of
mixing it up to form an emulsion that will not filter out
very effectively.

The path should be, a basket strainer to catch the chunks, a
separarator/filter to eliminate the bulk of the water and
the smaller suspended particles, the pump, then the finer
stages of filtration.

This is all assuming you don't have access to a centrifuge
which is really the best way to handle the process.

Rick

Steven Shelikoff wrote:

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

The difference is that if the pump suction pulls water and
fuel directly from the tank it will do an excellent job of
mixing it up to form an emulsion that will not filter out
very effectively.

The path should be, a basket strainer to catch the chunks, a
separarator/filter to eliminate the bulk of the water and
the smaller suspended particles, the pump, then the finer
stages of filtration.

This is all assuming you don't have access to a centrifuge
which is really the best way to handle the process.

Rick

After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.


article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

I think I'll put the pump between the filters. 10 micron on
the vacuum side, 1 micron on the pressure side.

Doug
s/v Callista

"Rich Hampel" wrote in message
...
After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.


article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

I think I'll put the pump between the filters. 10 micron on
the vacuum side, 1 micron on the pressure side.

Doug
s/v Callista

"Rich Hampel" wrote in message
...
After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.


article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

On Thu, 08 Jan 2004 14:24:02 GMT, Rich Hampel
wrote:

After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.

Not only shouldn't it make a difference due to the direction of motive
pressure, but the direction of motive pressure is the same in both
cases. Higher pressure on the inlet, lower on the outlet with the same
differential as well. If there really is a difference, then there must
be some other mechanism at work other than just whether the pump is
pushing or pulling.

Steve
article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

On Thu, 08 Jan 2004 14:24:02 GMT, Rich Hampel
wrote:

After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.

Not only shouldn't it make a difference due to the direction of motive
pressure, but the direction of motive pressure is the same in both
cases. Higher pressure on the inlet, lower on the outlet with the same
differential as well. If there really is a difference, then there must
be some other mechanism at work other than just whether the pump is
pushing or pulling.

Steve
article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

After 30 years of screwing around with this stuff I cant still give a
an accurate technical reason .... my 'opinion' is the 'regime' of
particle depositionIn and the formation of 'filter cake' ..... on a
pressure filtration the deposition begins mostly on the upper surface
or at least within 5% depth of the surface, while with vacuum
filtration the deposition is essentially INSIDE the matrix of the
media. Being inside the matrix causes higher internal velocities
which drive the particles deeper and deeper into the matrix ... causing
an exponential decrease in service life. ..... its the same for depth
as well as membrane filtration.
The quandy is that the fluids are incompressible and shouldnt make any
difference due to the direction of motive pressure .... but in practice
it does, it always does.


article , Steven Shelikoff
wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). The smaller the retention size of the filter media the
more efficient the coalescing efficiency.
On the very bottom of the filter bowl, add a pigtail of oil compatible
transluscent plastic tube (Tygon, etc.) with a cock on the end ....
when you see water in the pigtail simply drain the bowl. Thats the
same way a racor with an integral clear plastic knock-out-pot works.

If you are regularly polishing the fuel the coalesced emulsions will be
removed/trapped in the inverted filter bowl .... that why you put the
dip tube for the recirc system at the VERY bottom of the tank and a
drain cock on the inverted filter bowl.

Dont want air leaks or fuel oil leaks ------ dont use compression
fittings, use flared or better fittings.

Pump should have a SCREEN (preferably integral) for protection to
prevent damage by *huge* particles that would tear the rubber impeller
or wobble plate.

I say again, if you want long service life and efficient filtration
employ PRESSURE filtration, especially on a recirculation system.

The ONLY reason I can think of why fuel systems in boats use vacuum
filtration is ........... the engine manufactures supply the lift pump
and 'guard' filter - and puts it on the engine ...... and not on the
tank (where it SHOULD BE). Cheap and dirty solution, easier for the
boat builder - less wiring, less design, less effort, ....

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve

On Thu, 08 Jan 2004 05:54:34 GMT, (Steven
Shelikoff) wrote:

On Thu, 08 Jan 2004 02:51:46 GMT, Rich Hampel
wrote:

NOPE!
In pressure mode, the filter will also act as a 'coalescer' (bringing
similar surface tension fluids together to make larger and larger sized
particles) and such particles will settle out into a 'drop-out-pot'
..... or usually into the bottom of the filter bowl (bowl pointing
downwards). ///

All this begs the question, why does the filter media care whether it's
in "pressure" mode or "vacuum" mode? Sure, the plumbing and filter
cases care. But the media only sees a pressure differential across it.
What's the difference to the media if the there is 14psi (atmospheric
pressure) on one side and, say, 10 psi (a 4 psi vacuum drawing fuel
across the media) on the other side vs. 18 psi (4 psi pressure pushing
fuel across the media) on one side and 14 psi (atmospheric) on the
other?

IOW, even if the pump is past the filter drawing fuel through it, the
filter is still in "pressure" mode because it's really the atmospheric
pressure pushing fuel through the filter.

Steve


Looks like the contribution that mentioned a pressure pump's tendency
to mix and chop big water drops to a clogging emulsion where the
vacuum pump sucks them into the filter intact - that idea didn't
appeal to you?

Brian W