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#331
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Fuel transfer/polishing pump
Rich,
I appreciate that you seem to be an expert on filtering theory even though you also seem to lack the practical experience of actually using the TP or PT depth filters we're talking about. I realize you don't think they work. Even so, I'd love to hear your expert opinion (absolutely no sarcasm intened) on why my Racor 2uM filter has lasted so long (2 years now and still not clogged) after installing a TP prefilter when I completely clogged two of the same filters in 20 minutes each before installing the TP prefilter. Steve |
#332
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Fuel transfer/polishing pump
Steve,
I like your system. It seems like a reasonable approach. One thing I would like to be able to do is polish one tank while using the other though. One point that Rich makes is that a recirc system can move fuel much faster due to the the large effective pore size of the depth filter. Placing a 2 uM filter after the TP filter does negate that advantage. I was planning on doing exactly that as well because the TP filter would seem to be susseptable to shedding. It sounds from your experience that is not the case. Perhaps there is a little bit of shedding right at the beginning but anything shed would be quickly removed on a subsequent pass or by the engine filters. Doug "Steven Shelikoff" wrote in message ... Rich, I appreciate that you seem to be an expert on filtering theory even though you also seem to lack the practical experience of actually using the TP or PT depth filters we're talking about. I realize you don't think they work. Even so, I'd love to hear your expert opinion (absolutely no sarcasm intened) on why my Racor 2uM filter has lasted so long (2 years now and still not clogged) after installing a TP prefilter when I completely clogged two of the same filters in 20 minutes each before installing the TP prefilter. Steve |
#333
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Fuel transfer/polishing pump
Steve,
I like your system. It seems like a reasonable approach. One thing I would like to be able to do is polish one tank while using the other though. One point that Rich makes is that a recirc system can move fuel much faster due to the the large effective pore size of the depth filter. Placing a 2 uM filter after the TP filter does negate that advantage. I was planning on doing exactly that as well because the TP filter would seem to be susseptable to shedding. It sounds from your experience that is not the case. Perhaps there is a little bit of shedding right at the beginning but anything shed would be quickly removed on a subsequent pass or by the engine filters. Doug "Steven Shelikoff" wrote in message ... Rich, I appreciate that you seem to be an expert on filtering theory even though you also seem to lack the practical experience of actually using the TP or PT depth filters we're talking about. I realize you don't think they work. Even so, I'd love to hear your expert opinion (absolutely no sarcasm intened) on why my Racor 2uM filter has lasted so long (2 years now and still not clogged) after installing a TP prefilter when I completely clogged two of the same filters in 20 minutes each before installing the TP prefilter. Steve |
#334
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Fuel transfer/polishing pump
"LaBomba182" wrote in message ... Subject: Fuel transfer/polishing pump From: "Doug Dotson" It never fails in a thread that lasts this long that the personal insults start appearing. You haven't offered all that much useful anyway so won't miss the lack of any further contributions from you. That's an interesting take, considering you're the one who first implied that I had been drinking while responding to you. I would say that you failed to take my comment in the spirit that it was intended, that being a joke. It seems you can't take a joke. Seems that you can't either. Not to mention your poor reading in context skills. We all make mistakes. It was a mistake that you made that led to this sillyness. I just tried to make light of your mistake. As to useful information put forth, same to you. :-) I started this thread to gather information. Good luck with your "polishing" system. Thanks. I think it will work well. Capt. Bill |
#335
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Fuel transfer/polishing pump
"LaBomba182" wrote in message ... Subject: Fuel transfer/polishing pump From: "Doug Dotson" It never fails in a thread that lasts this long that the personal insults start appearing. You haven't offered all that much useful anyway so won't miss the lack of any further contributions from you. That's an interesting take, considering you're the one who first implied that I had been drinking while responding to you. I would say that you failed to take my comment in the spirit that it was intended, that being a joke. It seems you can't take a joke. Seems that you can't either. Not to mention your poor reading in context skills. We all make mistakes. It was a mistake that you made that led to this sillyness. I just tried to make light of your mistake. As to useful information put forth, same to you. :-) I started this thread to gather information. Good luck with your "polishing" system. Thanks. I think it will work well. Capt. Bill |
#336
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Fuel transfer/polishing pump
You are correct !!!
Most folks dont realize that a filter isnt a 'screen door' .... it can pass particulate LARGER than the 'rating'. :-) In article , Steven Shelikoff wrote: On Fri, 05 Dec 2003 05:28:01 GMT, Rich Hampel wrote: In article , Steven Shelikoff wrote: Why not just always leave the polishing system in-line? Allow for a bypass to change a filter or if it develops a vacuum leak, but other then that, there's nothing wrong with always using "just polished" fuel. My 'read' from your statment is that perhaps you miss the functional point of a recirculation filtration system - which is using a filter of LARGE pore/rentention size to eventually wind up with a fluid with very few very small particles. A recirc filter only removes a paltry few percent of the 'target' size particles (for example 5% of 2uM particles.). A large pore size filter will have very little resistance to flow, will have more permeability (open space), will have more ultimate 'dirt capacity'. If you pass the fluid 20 times through the filter, you will remove approximately a value approaching 100% of the target particles. With the same pump, a LARGE filter is be able to pass a LARGE volume very quickly, whereas 2uM filter will take longer (due to resistance to flow - pump slows down or starts to slip and fluid begins to bypass the vanes, etc. ). Actually, I do understand that it's best to recirculate fuel many times through the polishing system. That is what I do. But the engine has to draw fuel from somewhere and I don't see why it's not better to draw fuel from the outlet of the polishing system and always leave it on while the engine is running (most of the flow from the system goes back to the tank to be recirculated anyway) then to draw fuel directly from the tank. Doing it this way allows for the most fuel passes through the polishing system since it's running more often and because you get that "one last time through" that you wouldn't get if you draw from the tank. For single pass filtration (and without knowing the particle size distribution) one typically needs a prefilter of the same surface area (or dirt capacity) that is 5 times the size of the final filter. eg.: 10uM followed by 2uM, where the prefilter is used to prolong the life of the final filter. This is somewhat simplistic. When you design a filtration system with a prefilter or multistage prefilters one typically attempts to make ALL the filters fail at the exact same time - so maximum debris is removed and the cost of change is minimized - and you dont throw away filters that still have some capture ability left in them. Well, since we're talking about a polishing system and not single pass filtration, the above may not be applicable. But for a recirculating polishing system on our own boat where we do the filter changes ourselves, to make it most cost effective I'd design it not so that all of the filters fail at the exact same time but that the cost of filtering of each stage in a multistage system is the same. That is, if your second stage filter element costs 10x the first stage filter element I'd want that second stage element to last 10x longer before it needs to be replaced to be as cost effective. If you monitor each stage with independent vacuum gauges you won't be throwing away filters that still have some capture ability left in them. Steve |
#337
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Fuel transfer/polishing pump
You are correct !!!
Most folks dont realize that a filter isnt a 'screen door' .... it can pass particulate LARGER than the 'rating'. :-) In article , Steven Shelikoff wrote: On Fri, 05 Dec 2003 05:28:01 GMT, Rich Hampel wrote: In article , Steven Shelikoff wrote: Why not just always leave the polishing system in-line? Allow for a bypass to change a filter or if it develops a vacuum leak, but other then that, there's nothing wrong with always using "just polished" fuel. My 'read' from your statment is that perhaps you miss the functional point of a recirculation filtration system - which is using a filter of LARGE pore/rentention size to eventually wind up with a fluid with very few very small particles. A recirc filter only removes a paltry few percent of the 'target' size particles (for example 5% of 2uM particles.). A large pore size filter will have very little resistance to flow, will have more permeability (open space), will have more ultimate 'dirt capacity'. If you pass the fluid 20 times through the filter, you will remove approximately a value approaching 100% of the target particles. With the same pump, a LARGE filter is be able to pass a LARGE volume very quickly, whereas 2uM filter will take longer (due to resistance to flow - pump slows down or starts to slip and fluid begins to bypass the vanes, etc. ). Actually, I do understand that it's best to recirculate fuel many times through the polishing system. That is what I do. But the engine has to draw fuel from somewhere and I don't see why it's not better to draw fuel from the outlet of the polishing system and always leave it on while the engine is running (most of the flow from the system goes back to the tank to be recirculated anyway) then to draw fuel directly from the tank. Doing it this way allows for the most fuel passes through the polishing system since it's running more often and because you get that "one last time through" that you wouldn't get if you draw from the tank. For single pass filtration (and without knowing the particle size distribution) one typically needs a prefilter of the same surface area (or dirt capacity) that is 5 times the size of the final filter. eg.: 10uM followed by 2uM, where the prefilter is used to prolong the life of the final filter. This is somewhat simplistic. When you design a filtration system with a prefilter or multistage prefilters one typically attempts to make ALL the filters fail at the exact same time - so maximum debris is removed and the cost of change is minimized - and you dont throw away filters that still have some capture ability left in them. Well, since we're talking about a polishing system and not single pass filtration, the above may not be applicable. But for a recirculating polishing system on our own boat where we do the filter changes ourselves, to make it most cost effective I'd design it not so that all of the filters fail at the exact same time but that the cost of filtering of each stage in a multistage system is the same. That is, if your second stage filter element costs 10x the first stage filter element I'd want that second stage element to last 10x longer before it needs to be replaced to be as cost effective. If you monitor each stage with independent vacuum gauges you won't be throwing away filters that still have some capture ability left in them. Steve |
#338
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Fuel transfer/polishing pump
Rich,
What do you recommend for a depth filter rather then the TP ot PT filters? Doug "Rich Hampel" wrote in message ... You are correct !!! Most folks dont realize that a filter isnt a 'screen door' .... it can pass particulate LARGER than the 'rating'. :-) In article , Steven Shelikoff wrote: On Fri, 05 Dec 2003 05:28:01 GMT, Rich Hampel wrote: In article , Steven Shelikoff wrote: Why not just always leave the polishing system in-line? Allow for a bypass to change a filter or if it develops a vacuum leak, but other then that, there's nothing wrong with always using "just polished" fuel. My 'read' from your statment is that perhaps you miss the functional point of a recirculation filtration system - which is using a filter of LARGE pore/rentention size to eventually wind up with a fluid with very few very small particles. A recirc filter only removes a paltry few percent of the 'target' size particles (for example 5% of 2uM particles.). A large pore size filter will have very little resistance to flow, will have more permeability (open space), will have more ultimate 'dirt capacity'. If you pass the fluid 20 times through the filter, you will remove approximately a value approaching 100% of the target particles. With the same pump, a LARGE filter is be able to pass a LARGE volume very quickly, whereas 2uM filter will take longer (due to resistance to flow - pump slows down or starts to slip and fluid begins to bypass the vanes, etc. ). Actually, I do understand that it's best to recirculate fuel many times through the polishing system. That is what I do. But the engine has to draw fuel from somewhere and I don't see why it's not better to draw fuel from the outlet of the polishing system and always leave it on while the engine is running (most of the flow from the system goes back to the tank to be recirculated anyway) then to draw fuel directly from the tank. Doing it this way allows for the most fuel passes through the polishing system since it's running more often and because you get that "one last time through" that you wouldn't get if you draw from the tank. For single pass filtration (and without knowing the particle size distribution) one typically needs a prefilter of the same surface area (or dirt capacity) that is 5 times the size of the final filter. eg.: 10uM followed by 2uM, where the prefilter is used to prolong the life of the final filter. This is somewhat simplistic. When you design a filtration system with a prefilter or multistage prefilters one typically attempts to make ALL the filters fail at the exact same time - so maximum debris is removed and the cost of change is minimized - and you dont throw away filters that still have some capture ability left in them. Well, since we're talking about a polishing system and not single pass filtration, the above may not be applicable. But for a recirculating polishing system on our own boat where we do the filter changes ourselves, to make it most cost effective I'd design it not so that all of the filters fail at the exact same time but that the cost of filtering of each stage in a multistage system is the same. That is, if your second stage filter element costs 10x the first stage filter element I'd want that second stage element to last 10x longer before it needs to be replaced to be as cost effective. If you monitor each stage with independent vacuum gauges you won't be throwing away filters that still have some capture ability left in them. Steve |
#339
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Fuel transfer/polishing pump
Rich,
What do you recommend for a depth filter rather then the TP ot PT filters? Doug "Rich Hampel" wrote in message ... You are correct !!! Most folks dont realize that a filter isnt a 'screen door' .... it can pass particulate LARGER than the 'rating'. :-) In article , Steven Shelikoff wrote: On Fri, 05 Dec 2003 05:28:01 GMT, Rich Hampel wrote: In article , Steven Shelikoff wrote: Why not just always leave the polishing system in-line? Allow for a bypass to change a filter or if it develops a vacuum leak, but other then that, there's nothing wrong with always using "just polished" fuel. My 'read' from your statment is that perhaps you miss the functional point of a recirculation filtration system - which is using a filter of LARGE pore/rentention size to eventually wind up with a fluid with very few very small particles. A recirc filter only removes a paltry few percent of the 'target' size particles (for example 5% of 2uM particles.). A large pore size filter will have very little resistance to flow, will have more permeability (open space), will have more ultimate 'dirt capacity'. If you pass the fluid 20 times through the filter, you will remove approximately a value approaching 100% of the target particles. With the same pump, a LARGE filter is be able to pass a LARGE volume very quickly, whereas 2uM filter will take longer (due to resistance to flow - pump slows down or starts to slip and fluid begins to bypass the vanes, etc. ). Actually, I do understand that it's best to recirculate fuel many times through the polishing system. That is what I do. But the engine has to draw fuel from somewhere and I don't see why it's not better to draw fuel from the outlet of the polishing system and always leave it on while the engine is running (most of the flow from the system goes back to the tank to be recirculated anyway) then to draw fuel directly from the tank. Doing it this way allows for the most fuel passes through the polishing system since it's running more often and because you get that "one last time through" that you wouldn't get if you draw from the tank. For single pass filtration (and without knowing the particle size distribution) one typically needs a prefilter of the same surface area (or dirt capacity) that is 5 times the size of the final filter. eg.: 10uM followed by 2uM, where the prefilter is used to prolong the life of the final filter. This is somewhat simplistic. When you design a filtration system with a prefilter or multistage prefilters one typically attempts to make ALL the filters fail at the exact same time - so maximum debris is removed and the cost of change is minimized - and you dont throw away filters that still have some capture ability left in them. Well, since we're talking about a polishing system and not single pass filtration, the above may not be applicable. But for a recirculating polishing system on our own boat where we do the filter changes ourselves, to make it most cost effective I'd design it not so that all of the filters fail at the exact same time but that the cost of filtering of each stage in a multistage system is the same. That is, if your second stage filter element costs 10x the first stage filter element I'd want that second stage element to last 10x longer before it needs to be replaced to be as cost effective. If you monitor each stage with independent vacuum gauges you won't be throwing away filters that still have some capture ability left in them. Steve |
#340
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Fuel transfer/polishing pump
Please appreciate that I dont want to appear to be an arrogant
know-it-all after being in on and aroud critical filtration/separation most of mworking life ... and yet give just enough information that each can take and arrive a result that is based on current or state-of-the-art results. ANY filter media (including compressed pubic hair) thats used in a recirculation polishing system will work ... its all a matter of degree. Whats wrong with TP, etc. is that the material used to filter is not bonded, can digest (make more particles) in the presence of water --- thus to do the exact opposite of what you are trying to do. If doesnt matter if rust, bacteria or broken up toilet paper fibers blocks the final filter to your engine... expecially during an emergency. Unbonded cellulose is notorious for unloading particles or allowing the particles to migrate through the filter .... OK if the main system is not drawing fuel thats OK as the recirculating slurry will probably be recaptured; but, if all hell breaks loose and you have a high fuel demand at the time when the TP decides to unload itself or its already trapped debris .... the whole system can catastrophically fail .... My objection to TP - very poor efficiency, migrates particles, migrates fibers, unloads at increasing differential pressure, larger first cost due to need for larger diameter housing, no constancy of retention, knife edge seals of 'cartridge' - very limited in retention and VERY prone to bypass. Short life due to low surface area. TP will ' deform' - wrinkle into a smaller mass when heavily laden and differential pressure is high (remember those knife edge seals) then unload and bypass. As far as experience ..... the high tech/high purity industry used such devices for many years: loose fiberglass, Kotex pads, string wound cylinders, TP, chopped cellulose ....... until after WWII the world started using captured German technology: membranes, cartridges, etc. If TP were any good, industry would still be using it. The last such system I personally replaced/upgraded was in the mid 70s. ..... as a cost cutting measure!!!!! DO NOT depend on filters to remove the crud in your system. If they plug it means that you are contaminated and need to clean your fuel system. Such plugging clearly indicates a **symptom**, the filters prevented the symptom from becoming an extremis situation. If your system is plugging filters, they did do their job as they are supposed to .... but now go back in and clean the system! Resident particles form and agglomerate into more particles. Bacterial scums feed other bacteria, etc. Your symptoms of plugging filters means your system is contaminated.... a filtration system is a band-aid or a 'condom' to prevent stoppage. Consider to thoroughly mechanically CLEAN the tank. ;-) In article , Steven Shelikoff wrote: Rich, I appreciate that you seem to be an expert on filtering theory even though you also seem to lack the practical experience of actually using the TP or PT depth filters we're talking about. I realize you don't think they work. Even so, I'd love to hear your expert opinion (absolutely no sarcasm intened) on why my Racor 2uM filter has lasted so long (2 years now and still not clogged) after installing a TP prefilter when I completely clogged two of the same filters in 20 minutes each before installing the TP prefilter. Steve |
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