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Fuel Polishing again.
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 |
Fuel Polishing again.
On Thu, 08 Jan 2004 14:53:44 GMT, Rick wrote:
Steven Shelikoff wrote: Well, now I have to ask why the pump should be before the finer stages of filtration. Because you can install canned filters which are rated for high pressure downstream of the pump, on the pressure side. The filters on the suction side are fairly coarse, produce little resistance to flow until clogged, and can perform the initial separation of water and solids. wouldn't matter where the pump is. Of course if it can't do that (not enough suction for all the stages before it) then you'd have to move the pump up in the stream like you suggest above. If the pump was upstream of all filters, so that it sucked through them all, the differential available is pretty low. That all depends on how many "all" is, the max pressure differential you want to operate at and how much vacuum the pump can draw. 2 stages should be fine. 3, probably not. That is why most installations use Racors on the suction side for the reasons I have given and then the final filters are can filters on the pressure side. I have 3 stages with an electric pump between the 2nd and 3rd and then the engine lift pump after the 3rd. Works pretty good. The only time it stopped working, leading me to thinking there was a vacuum leak, was when the tank vent clogged and vacuum built up in the tank to the point where fuel couldn't be drawn out anymore. Problem solved temporarily by opening the filler. Steve |
Fuel Polishing again.
On Thu, 08 Jan 2004 14:53:44 GMT, Rick wrote:
Steven Shelikoff wrote: Well, now I have to ask why the pump should be before the finer stages of filtration. Because you can install canned filters which are rated for high pressure downstream of the pump, on the pressure side. The filters on the suction side are fairly coarse, produce little resistance to flow until clogged, and can perform the initial separation of water and solids. wouldn't matter where the pump is. Of course if it can't do that (not enough suction for all the stages before it) then you'd have to move the pump up in the stream like you suggest above. If the pump was upstream of all filters, so that it sucked through them all, the differential available is pretty low. That all depends on how many "all" is, the max pressure differential you want to operate at and how much vacuum the pump can draw. 2 stages should be fine. 3, probably not. That is why most installations use Racors on the suction side for the reasons I have given and then the final filters are can filters on the pressure side. I have 3 stages with an electric pump between the 2nd and 3rd and then the engine lift pump after the 3rd. Works pretty good. The only time it stopped working, leading me to thinking there was a vacuum leak, was when the tank vent clogged and vacuum built up in the tank to the point where fuel couldn't be drawn out anymore. Problem solved temporarily by opening the filler. Steve |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 |
Fuel Polishing again.
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Fuel Polishing again.
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Fuel Polishing again.
On 08 Jan 2004 11:23:20 +0100, Ole-Hjalmar Kristensen
wrote: "R" == Rick writes: /// R This is all assuming you don't have access to a centrifuge which is R really the best way to handle the process. R Rick Do you happen to know if there is any centrifugal separator on the market suited to small boats? I cannot really think of any technical reasons why not, but perhaps the market isn't there. Btw., I once had a Scania truck diesel engine which had a centrifuge for its lubrication oil. Judging from the amount of gunk it separated out of the oil, it worked very well. Now *that* is an interesting question! The pneumatic tube freezer/heater comes to mind immediately. I can't recall the appropriate name - but the principle is incredibly simple: introduce the pressurized fluid tangentially to a short cylinder, and at one end of the cylinder, the spinning fluid meets a washer with a central hole - the lighter fraction goes through here. At the other end of the cylinder, the spinning fluid meets a central barrier, with an annular gap - so the heavier fraction goes through here. You can make them with plumbing fittings and minimal machining or filing. With pressurized air, these gadgets separate cooled air from heated air (though the power efficiency is not compretitive with regular fridges...) With pressurized fuel, this gadget ought to do a very creditable job of spinning out water and particles.... Brian Whatcott Altus OK |
Fuel Polishing again.
On 08 Jan 2004 11:23:20 +0100, Ole-Hjalmar Kristensen
wrote: "R" == Rick writes: /// R This is all assuming you don't have access to a centrifuge which is R really the best way to handle the process. R Rick Do you happen to know if there is any centrifugal separator on the market suited to small boats? I cannot really think of any technical reasons why not, but perhaps the market isn't there. Btw., I once had a Scania truck diesel engine which had a centrifuge for its lubrication oil. Judging from the amount of gunk it separated out of the oil, it worked very well. Now *that* is an interesting question! The pneumatic tube freezer/heater comes to mind immediately. I can't recall the appropriate name - but the principle is incredibly simple: introduce the pressurized fluid tangentially to a short cylinder, and at one end of the cylinder, the spinning fluid meets a washer with a central hole - the lighter fraction goes through here. At the other end of the cylinder, the spinning fluid meets a central barrier, with an annular gap - so the heavier fraction goes through here. You can make them with plumbing fittings and minimal machining or filing. With pressurized air, these gadgets separate cooled air from heated air (though the power efficiency is not compretitive with regular fridges...) With pressurized fuel, this gadget ought to do a very creditable job of spinning out water and particles.... Brian Whatcott Altus OK |
Fuel Polishing again.
On Fri, 09 Jan 2004 00:59:52 GMT, Brian Whatcott
wrote: 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? Sure did. So does the idea that I'd rather have a malfunction that lets air into the system than one that lets fuel out. But both of those points leads to the conclusion that you should suck fuel through the filter rather than push it through. However, Rich recommends that fuel be pushed through due to some tendency of the filter media to work better in that mode. Thus my question, discounting all other aspects at hand such as the pump emulsifying the fuel before it gets to the filter, why does the filter media care which side the pump is on? Fuel is being pushed through it either way, either by the pump with a higher pressure on the inlet or the atmosphere with a higher pressure on the inlet. Steve |
Fuel Polishing again.
Steven Shelikoff wrote:
However, Rich recommends that fuel be pushed through due to some tendency of the filter media to work better in that mode. I recommend sucking fuel through the primary separator filters. The much finer secondary filters normally require pressure feed to assure adequate flow through a reasonable sized element. The canned type of filter is designed to work under high pressure and are used very successfully and safely in that mode by nearly every manufacturer of large and small engines. During many years of operating such filters in marine applications the only time I have see one leak badly was when the discharge from the filter was closed against the positive displacement pump serving it. And in that case all that happened was the rubber sealing ring blew out. Opening the valve stopped the leak immediately. ... discounting all other aspects at hand such as the pump emulsifying the fuel before it gets to the filter, why does the filter media care which side the pump is on? Fuel is being pushed through it either way, either by the pump with a higher pressure on the inlet or the atmosphere with a higher pressure on the inlet. 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. It does not take much imagination to see that the same flow and pressure can be applied to a filter housing by gravity, a pump discharge or a pump suction. Rick |
Fuel Polishing again.
Steven Shelikoff wrote:
However, Rich recommends that fuel be pushed through due to some tendency of the filter media to work better in that mode. I recommend sucking fuel through the primary separator filters. The much finer secondary filters normally require pressure feed to assure adequate flow through a reasonable sized element. The canned type of filter is designed to work under high pressure and are used very successfully and safely in that mode by nearly every manufacturer of large and small engines. During many years of operating such filters in marine applications the only time I have see one leak badly was when the discharge from the filter was closed against the positive displacement pump serving it. And in that case all that happened was the rubber sealing ring blew out. Opening the valve stopped the leak immediately. ... discounting all other aspects at hand such as the pump emulsifying the fuel before it gets to the filter, why does the filter media care which side the pump is on? Fuel is being pushed through it either way, either by the pump with a higher pressure on the inlet or the atmosphere with a higher pressure on the inlet. 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. It does not take much imagination to see that the same flow and pressure can be applied to a filter housing by gravity, a pump discharge or a pump suction. Rick |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 |
Fuel Polishing again.
Its the way that the deposition of debris in a filter behaves, if you
build the 'cake' inside the filter media the life of the filter becomes very short in comparison to 'cake' formation on or 'immediately inside' the surface. There is a valid doctoral discertation awating the person who solves this dilemma ... so far no one can fully explain it, and the filtration industry will stand pat on pressure filtration vs. vacuum filtration .... all based on actual performance data. In article , Steven Shelikoff wrote: On Fri, 09 Jan 2004 00:59:52 GMT, Brian Whatcott wrote: 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? Sure did. So does the idea that I'd rather have a malfunction that lets air into the system than one that lets fuel out. But both of those points leads to the conclusion that you should suck fuel through the filter rather than push it through. However, Rich recommends that fuel be pushed through due to some tendency of the filter media to work better in that mode. Thus my question, discounting all other aspects at hand such as the pump emulsifying the fuel before it gets to the filter, why does the filter media care which side the pump is on? Fuel is being pushed through it either way, either by the pump with a higher pressure on the inlet or the atmosphere with a higher pressure on the inlet. Steve |
Fuel Polishing again.
Its the way that the deposition of debris in a filter behaves, if you
build the 'cake' inside the filter media the life of the filter becomes very short in comparison to 'cake' formation on or 'immediately inside' the surface. There is a valid doctoral discertation awating the person who solves this dilemma ... so far no one can fully explain it, and the filtration industry will stand pat on pressure filtration vs. vacuum filtration .... all based on actual performance data. In article , Steven Shelikoff wrote: On Fri, 09 Jan 2004 00:59:52 GMT, Brian Whatcott wrote: 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? Sure did. So does the idea that I'd rather have a malfunction that lets air into the system than one that lets fuel out. But both of those points leads to the conclusion that you should suck fuel through the filter rather than push it through. However, Rich recommends that fuel be pushed through due to some tendency of the filter media to work better in that mode. Thus my question, discounting all other aspects at hand such as the pump emulsifying the fuel before it gets to the filter, why does the filter media care which side the pump is on? Fuel is being pushed through it either way, either by the pump with a higher pressure on the inlet or the atmosphere with a higher pressure on the inlet. Steve |
Fuel Polishing again.
Rich Hampel wrote:
The use of a centrifuge on the small volume boat tankage .... borders on ludicrous. your opinion is not universal. Besides, we were writing about FUEL POLISHING ... an activity normally performed alongside a dock at rather extended intervals. Centrifuges are extreme high maintenance rotating and power consuming equipment Just because you don't like them ... and you have a peculiar vision of "extreme" maintenance. 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. A rather extremist position. There are plenty of boats under 75 feet that use a centrifuge to handle fuel separation tasks. Why do you think Alfa Laval build one the size of a gallon milk jug? Your personal view and experience does not define the marine industry in the 21st century. Do you also use a nephalometer to arrive at when the centrifugation is complete? Once through will do. 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. Water does not increase the cetane number ... do you know what that means anyway? Water serves to reduce the temperature of combustion and thereby reduce the formation of oxides of nitrogen in a diesel. Its the FREE water thats the 'problem' as simply 'slugs' of free water simply do not burn. Got that one wrong too. There are several techniques available in large diesels that layer the fuel and water injected, and another that injects water first then fuel. Let's stick to filtration and fuel polishing. If you want to have a snit go chat with K over on rec. boats. Rick |
Fuel Polishing again.
Rich Hampel wrote:
The use of a centrifuge on the small volume boat tankage .... borders on ludicrous. your opinion is not universal. Besides, we were writing about FUEL POLISHING ... an activity normally performed alongside a dock at rather extended intervals. Centrifuges are extreme high maintenance rotating and power consuming equipment Just because you don't like them ... and you have a peculiar vision of "extreme" maintenance. 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. A rather extremist position. There are plenty of boats under 75 feet that use a centrifuge to handle fuel separation tasks. Why do you think Alfa Laval build one the size of a gallon milk jug? Your personal view and experience does not define the marine industry in the 21st century. Do you also use a nephalometer to arrive at when the centrifugation is complete? Once through will do. 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. Water does not increase the cetane number ... do you know what that means anyway? Water serves to reduce the temperature of combustion and thereby reduce the formation of oxides of nitrogen in a diesel. Its the FREE water thats the 'problem' as simply 'slugs' of free water simply do not burn. Got that one wrong too. There are several techniques available in large diesels that layer the fuel and water injected, and another that injects water first then fuel. Let's stick to filtration and fuel polishing. If you want to have a snit go chat with K over on rec. boats. Rick |
Fuel Polishing again.
Rich Hampel wrote:
There is a valid doctoral discertation awating the person who solves this dilemma ... It is not a dilemma that keeps many boaters awake at night, trust me. Rick |
Fuel Polishing again.
Rich Hampel wrote:
There is a valid doctoral discertation awating the person who solves this dilemma ... It is not a dilemma that keeps many boaters awake at night, trust me. Rick |
Fuel Polishing again.
In article t,
Rick wrote: Rich Hampel wrote: There is a valid doctoral discertation awating the person who solves this dilemma ... It is not a dilemma that keeps many boaters awake at night, trust me. Rick It's keeping SOME boaters awake tonight ;-) -- 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/ |
Fuel Polishing again.
In article t,
Rick wrote: Rich Hampel wrote: There is a valid doctoral discertation awating the person who solves this dilemma ... It is not a dilemma that keeps many boaters awake at night, trust me. Rick It's keeping SOME boaters awake tonight ;-) -- 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/ |
Fuel Polishing again.
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. The casing is a different story. For instance, I don't feel that the Racor 500's center-screw, edge-seal casing could handle "high" pressure. It "feels" safer to limit it to the 14.7# maximum vacuum differential. In addition, the 500's plastic bowl seems quite adequate for up to 15# suction, but I'm not sure I'd trust it to 15# (or more) pressure. -- 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/ |
Fuel Polishing again.
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. The casing is a different story. For instance, I don't feel that the Racor 500's center-screw, edge-seal casing could handle "high" pressure. It "feels" safer to limit it to the 14.7# maximum vacuum differential. In addition, the 500's plastic bowl seems quite adequate for up to 15# suction, but I'm not sure I'd trust it to 15# (or more) pressure. -- 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/ |
Fuel Polishing again.
You are probably thinking of a Hilsch vortex tube. I agree, they are
neat devices. For seaparation, a hydrocyclone would also be a possibility, but I imaginge they do not get rid of the really fine particles as efficiently as a centrifuge. While looking around yesterday, I stumbled over an interesting device here, which has no moving parts and works along the same lines: http://www.quantum-dynamics.com/Centrifugal.html "BW" == Brian Whatcott writes: BW On 08 Jan 2004 11:23:20 +0100, Ole-Hjalmar Kristensen BW wrote: "R" == Rick writes: BW /// R This is all assuming you don't have access to a centrifuge which is R really the best way to handle the process. R Rick Do you happen to know if there is any centrifugal separator on the market suited to small boats? I cannot really think of any technical reasons why not, but perhaps the market isn't there. Btw., I once had a Scania truck diesel engine which had a centrifuge for its lubrication oil. Judging from the amount of gunk it separated out of the oil, it worked very well. BW Now *that* is an interesting question! BW The pneumatic tube freezer/heater comes to mind immediately. BW I can't recall the appropriate name - but the principle is incredibly BW simple: introduce the pressurized fluid tangentially to a short BW cylinder, and at one end of the cylinder, the spinning fluid meets a BW washer with a central hole - the lighter fraction goes through here. BW At the other end of the cylinder, the spinning fluid meets a central BW barrier, with an annular gap - so the heavier fraction goes through BW here. You can make them with plumbing fittings and minimal BW machining or filing. BW With pressurized air, these gadgets separate cooled air from heated BW air (though the power efficiency is not compretitive with BW regular fridges...) BW With pressurized fuel, this gadget ought to do a very creditable job BW of spinning out water and particles.... BW Brian Whatcott Altus OK -- This page intentionally left blank |
Fuel Polishing again.
You are probably thinking of a Hilsch vortex tube. I agree, they are
neat devices. For seaparation, a hydrocyclone would also be a possibility, but I imaginge they do not get rid of the really fine particles as efficiently as a centrifuge. While looking around yesterday, I stumbled over an interesting device here, which has no moving parts and works along the same lines: http://www.quantum-dynamics.com/Centrifugal.html "BW" == Brian Whatcott writes: BW On 08 Jan 2004 11:23:20 +0100, Ole-Hjalmar Kristensen BW wrote: "R" == Rick writes: BW /// R This is all assuming you don't have access to a centrifuge which is R really the best way to handle the process. R Rick Do you happen to know if there is any centrifugal separator on the market suited to small boats? I cannot really think of any technical reasons why not, but perhaps the market isn't there. Btw., I once had a Scania truck diesel engine which had a centrifuge for its lubrication oil. Judging from the amount of gunk it separated out of the oil, it worked very well. BW Now *that* is an interesting question! BW The pneumatic tube freezer/heater comes to mind immediately. BW I can't recall the appropriate name - but the principle is incredibly BW simple: introduce the pressurized fluid tangentially to a short BW cylinder, and at one end of the cylinder, the spinning fluid meets a BW washer with a central hole - the lighter fraction goes through here. BW At the other end of the cylinder, the spinning fluid meets a central BW barrier, with an annular gap - so the heavier fraction goes through BW here. You can make them with plumbing fittings and minimal BW machining or filing. BW With pressurized air, these gadgets separate cooled air from heated BW air (though the power efficiency is not compretitive with BW regular fridges...) BW With pressurized fuel, this gadget ought to do a very creditable job BW of spinning out water and particles.... BW Brian Whatcott Altus OK -- This page intentionally left blank |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
"Rick" wrote in message k.net... Rich Hampel wrote: The use of a centrifuge on the small volume boat tankage .... borders on ludicrous. your opinion is not universal. Besides, we were writing about FUEL POLISHING ... an activity normally performed alongside a dock at rather extended intervals. 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. Centrifuges are extreme high maintenance rotating and power consuming equipment Just because you don't like them ... and you have a peculiar vision of "extreme" maintenance. Not practical for the type of system we are talking about here. 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. A rather extremist position. There are plenty of boats under 75 feet that use a centrifuge to handle fuel separation tasks. Why do you think Alfa Laval build one the size of a gallon milk jug? Your personal view and experience does not define the marine industry in the 21st century. Do you also use a nephalometer to arrive at when the centrifugation is complete? Once through will do. 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. Water does not increase the cetane number ... do you know what that means anyway? Water serves to reduce the temperature of combustion and thereby reduce the formation of oxides of nitrogen in a diesel. Its the FREE water thats the 'problem' as simply 'slugs' of free water simply do not burn. Got that one wrong too. There are several techniques available in large diesels that layer the fuel and water injected, and another that injects water first then fuel. Let's stick to filtration and fuel polishing. If you want to have a snit go chat with K over on rec. boats. Rick |
Fuel Polishing again.
"Rick" wrote in message k.net... Rich Hampel wrote: The use of a centrifuge on the small volume boat tankage .... borders on ludicrous. your opinion is not universal. Besides, we were writing about FUEL POLISHING ... an activity normally performed alongside a dock at rather extended intervals. 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. Centrifuges are extreme high maintenance rotating and power consuming equipment Just because you don't like them ... and you have a peculiar vision of "extreme" maintenance. Not practical for the type of system we are talking about here. 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. A rather extremist position. There are plenty of boats under 75 feet that use a centrifuge to handle fuel separation tasks. Why do you think Alfa Laval build one the size of a gallon milk jug? Your personal view and experience does not define the marine industry in the 21st century. Do you also use a nephalometer to arrive at when the centrifugation is complete? Once through will do. 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. Water does not increase the cetane number ... do you know what that means anyway? Water serves to reduce the temperature of combustion and thereby reduce the formation of oxides of nitrogen in a diesel. Its the FREE water thats the 'problem' as simply 'slugs' of free water simply do not burn. Got that one wrong too. There are several techniques available in large diesels that layer the fuel and water injected, and another that injects water first then fuel. Let's stick to filtration and fuel polishing. If you want to have a snit go chat with K over on rec. boats. Rick |
Fuel Polishing again.
I don't think the typical Walbro fuel pump can pull such a vacuum.
Doug "Rich Hampel" wrote in message ... 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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
I don't think the typical Walbro fuel pump can pull such a vacuum.
Doug "Rich Hampel" wrote in message ... 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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
most single stage pumps will deliver approx 6" vacuum when
'deadheaded', at least thats what you design for as a maximum. ..... unless you have the manufacturers documents that include 'slip', etc. In article , Doug Dotson wrote: I don't think the typical Walbro fuel pump can pull such a vacuum. Doug "Rich Hampel" wrote in message ... 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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
most single stage pumps will deliver approx 6" vacuum when
'deadheaded', at least thats what you design for as a maximum. ..... unless you have the manufacturers documents that include 'slip', etc. In article , Doug Dotson wrote: I don't think the typical Walbro fuel pump can pull such a vacuum. Doug "Rich Hampel" wrote in message ... 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 #2 diesel fuel but you must understand that #2 is a mix of various fractions. From that standpoint alone and the potential of 'flashing by vacuum application make vacuum a less conservative approach to fuel delivery systems. |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 |
Fuel Polishing again.
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 |
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