|
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 |
Fuel Polishing again.
Changing the oil every 100 hours isn't much of a chore. My engine
only holds 2 gallons. 110VAC polishing systems would be a pain when at ancor or under sail. Can't justify running the genset for hours on end. A nice 12VDC pump drawing just a few amps can be supported easier on PV and wind.\\ Doug s/v Callista "Rick" wrote in message .net... Doug Dotson wrote: Actually, we are talking about permanently installed polishing systems that run for extended periods of time. In general, they run the entire time the engine iss running and also when the boat is sitting at anchor or at a dock they run for several hours per week. OK, in that case I would look very closely at the Alfa Laval unit. It is very small, 110VAC low power. No filter beats a centrifuge for use like that. If I really wanted to do it right I would put one on the lube oil as well. Rick |
Fuel Polishing again.
Changing the oil every 100 hours isn't much of a chore. My engine
only holds 2 gallons. 110VAC polishing systems would be a pain when at ancor or under sail. Can't justify running the genset for hours on end. A nice 12VDC pump drawing just a few amps can be supported easier on PV and wind.\\ Doug s/v Callista "Rick" wrote in message .net... Doug Dotson wrote: Actually, we are talking about permanently installed polishing systems that run for extended periods of time. In general, they run the entire time the engine iss running and also when the boat is sitting at anchor or at a dock they run for several hours per week. OK, in that case I would look very closely at the Alfa Laval unit. It is very small, 110VAC low power. No filter beats a centrifuge for use like that. If I really wanted to do it right I would put one on the lube oil as well. Rick |
Fuel Polishing again.
In article ,
(Steven Shelikoff) wrote: On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote: In article , Rick wrote: The element cannot possibly know what mechanism is used to establish fluid flow through the filter. The only thing the filter sees is rate of flow and as it clogs, differential. Anyone who claims otherwise is ignoring some other factor or talking BS. ONLY if you're only looking at the filter. We are only looking at the filter, not taking into account the casing, plumbing, etc. Steve I believe that the case is a pretty major component to ignore in a polishing system. A case designed for partial vacuum may not properly handle whatever pressure the pump can deliver. If the company says "only suction", I suspect it wasn't designed for pressure. Getting back to the filter alone: Since I believe most pumps can "push" better than they can "pull", we should also consider the maximum differential the filter can handle before it tears or otherwise breaks down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can these pumps deliver? -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Fuel Polishing again.
Jere Lull wrote:
I believe that the case is a pretty major component to ignore in a polishing system. You must have missed quite a few posts. The discussion you entered was about the mechanism for moving a fluid across the filter element. We were not discussing the entire filter assembly or its place in the system. Rick |
Fuel Polishing again.
Jere Lull wrote:
I believe that the case is a pretty major component to ignore in a polishing system. You must have missed quite a few posts. The discussion you entered was about the mechanism for moving a fluid across the filter element. We were not discussing the entire filter assembly or its place in the system. Rick |
Fuel Polishing again.
In article . net,
Rick wrote: Jere Lull wrote: I believe that the case is a pretty major component to ignore in a polishing system. You must have missed quite a few posts. The discussion you entered was about the mechanism for moving a fluid across the filter element. We were not discussing the entire filter assembly or its place in the system. Rick I *had* read the whole thread, and felt that it had lost its way, talking theoretically about just the filter when a real-life system includes quite a bit more. I didn't even mention the 4 or more extra joints that would be probable problem points if pressurized. The time we got a plugged tank pickup, I found out that one or more of our joints leaked air into the system. They don't give us any problem under normal operation. I strongly suspect that if I pressurized the system, that/those joint(s) would drip fuel very slowly. While not a safety problem with diesel, it's a mess I want to avoid. (The first mate is strongly affected by the smell. If she ain't happy, ain't no one happy!) They're all torqued to spec, so I'd have to exceed recommended torque(s) to stop the leak(s). -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Fuel Polishing again.
In article . net,
Rick wrote: Jere Lull wrote: I believe that the case is a pretty major component to ignore in a polishing system. You must have missed quite a few posts. The discussion you entered was about the mechanism for moving a fluid across the filter element. We were not discussing the entire filter assembly or its place in the system. Rick I *had* read the whole thread, and felt that it had lost its way, talking theoretically about just the filter when a real-life system includes quite a bit more. I didn't even mention the 4 or more extra joints that would be probable problem points if pressurized. The time we got a plugged tank pickup, I found out that one or more of our joints leaked air into the system. They don't give us any problem under normal operation. I strongly suspect that if I pressurized the system, that/those joint(s) would drip fuel very slowly. While not a safety problem with diesel, it's a mess I want to avoid. (The first mate is strongly affected by the smell. If she ain't happy, ain't no one happy!) They're all torqued to spec, so I'd have to exceed recommended torque(s) to stop the leak(s). -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Fuel Polishing again.
On Fri, 09 Jan 2004 14:47:50 GMT, Rich Hampel
wrote: Another good reason NOT to pull vacuum on fuels and other volitile liquids is that if the vacuum exceeds the vapor pressure of the fluid the liquid with boil (flash) or you will separate out the lighter fractions (lighter weight hydrocarbons). If youve ever had a gasoline that had 'vapor-lock' problems you'll understand this phenomenom. I dont have by me at this time a listing of the vapor pressure range of That's pretty much self regulating in this case. I.e., if you had a pump that was strong enough to create a vapor lock due to a very high vacuum, it would stop pumping and the vacuum would decrease and the vapor lock would be cured. But then again, if you had so much of a pressure difference on most of the filters we're talking about here that the fuel boils due to the vacuum of being drawn through the filter, it's time to change the element anyway. Either that or the pump is too strong and will destroy the filter. Steve |
Fuel Polishing again.
On Fri, 09 Jan 2004 14:47:50 GMT, Rich Hampel
wrote: Another good reason NOT to pull vacuum on fuels and other volitile liquids is that if the vacuum exceeds the vapor pressure of the fluid the liquid with boil (flash) or you will separate out the lighter fractions (lighter weight hydrocarbons). If youve ever had a gasoline that had 'vapor-lock' problems you'll understand this phenomenom. I dont have by me at this time a listing of the vapor pressure range of That's pretty much self regulating in this case. I.e., if you had a pump that was strong enough to create a vapor lock due to a very high vacuum, it would stop pumping and the vacuum would decrease and the vapor lock would be cured. But then again, if you had so much of a pressure difference on most of the filters we're talking about here that the fuel boils due to the vacuum of being drawn through the filter, it's time to change the element anyway. Either that or the pump is too strong and will destroy the filter. Steve |
Fuel Polishing again.
On Sat, 10 Jan 2004 05:40:18 GMT, Jere Lull wrote:
In article , (Steven Shelikoff) wrote: On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote: In article , Rick wrote: The element cannot possibly know what mechanism is used to establish fluid flow through the filter. The only thing the filter sees is rate of flow and as it clogs, differential. Anyone who claims otherwise is ignoring some other factor or talking BS. ONLY if you're only looking at the filter. We are only looking at the filter, not taking into account the casing, plumbing, etc. Steve I believe that the case is a pretty major component to ignore in a polishing system. A case designed for partial vacuum may not properly handle whatever pressure the pump can deliver. If the company says "only suction", I suspect it wasn't designed for pressure. When looking at the entire fuel polishing system, we're not ignoring the case. When looking strictly at the difference in the performance of the filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? Getting back to the filter alone: Since I believe most pumps can "push" better than they can "pull", we should also consider the maximum differential the filter can handle before it tears or otherwise breaks down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can these pumps deliver? Typical of the pumps used in this application is the Walbro 6802. I don't see the spec on vacuum for it on the web but it delivers 7 psi pressure so the vacuum is probably somewhat less. I do have the manual on the boat, but I'm not going down there anytime soom. In application, I haven't measured more than about 5 psi of vacuum before I changed elements. The Racors have no problem with 7 psi vacuum or pressure. Steve |
Fuel Polishing again.
On Sat, 10 Jan 2004 05:40:18 GMT, Jere Lull wrote:
In article , (Steven Shelikoff) wrote: On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote: In article , Rick wrote: The element cannot possibly know what mechanism is used to establish fluid flow through the filter. The only thing the filter sees is rate of flow and as it clogs, differential. Anyone who claims otherwise is ignoring some other factor or talking BS. ONLY if you're only looking at the filter. We are only looking at the filter, not taking into account the casing, plumbing, etc. Steve I believe that the case is a pretty major component to ignore in a polishing system. A case designed for partial vacuum may not properly handle whatever pressure the pump can deliver. If the company says "only suction", I suspect it wasn't designed for pressure. When looking at the entire fuel polishing system, we're not ignoring the case. When looking strictly at the difference in the performance of the filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? Getting back to the filter alone: Since I believe most pumps can "push" better than they can "pull", we should also consider the maximum differential the filter can handle before it tears or otherwise breaks down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can these pumps deliver? Typical of the pumps used in this application is the Walbro 6802. I don't see the spec on vacuum for it on the web but it delivers 7 psi pressure so the vacuum is probably somewhat less. I do have the manual on the boat, but I'm not going down there anytime soom. In application, I haven't measured more than about 5 psi of vacuum before I changed elements. The Racors have no problem with 7 psi vacuum or pressure. Steve |
Fuel Polishing again.
Steven Shelikoff wrote:
...filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? It's often a function of system and pump design. For e.g., when using a centrifugal pump (or liquid ring, and sometimes vane), the inlet is typically sized larger than the outlet. The result is higher fluid velocity on the outlet side versus the 'suction' side. Higher velocity, higher impact pressure, often resulting in better particulate retention. Additionally, all pump curves I've seen are, to some degree, more dependent on suction head than discharge head, and cavitation becomes an issue (i.e. efficiency drops more rapidly for loss of head on the suction side than for increase in head on the discharge side). Thus, when the filter begins to clog, you not only lose flowrate due to loop pressure drop increasing, you lose pump *efficiency* as well, exacerbating the problem. The result is, typically, less allowable filter loading before the system performance is affected, so more frequent filter changes. Whether this is an issue with the Racors or not, I have no idea, not being familiar with them. But if you want maximum system efficiency, maximum filter loading capacity, and longest interval between changeouts, discharge filtration is the way to go. Or...just use more *wind*, and all this diesel stuff is moot :-) Keith Hughes |
Fuel Polishing again.
Steven Shelikoff wrote:
...filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? It's often a function of system and pump design. For e.g., when using a centrifugal pump (or liquid ring, and sometimes vane), the inlet is typically sized larger than the outlet. The result is higher fluid velocity on the outlet side versus the 'suction' side. Higher velocity, higher impact pressure, often resulting in better particulate retention. Additionally, all pump curves I've seen are, to some degree, more dependent on suction head than discharge head, and cavitation becomes an issue (i.e. efficiency drops more rapidly for loss of head on the suction side than for increase in head on the discharge side). Thus, when the filter begins to clog, you not only lose flowrate due to loop pressure drop increasing, you lose pump *efficiency* as well, exacerbating the problem. The result is, typically, less allowable filter loading before the system performance is affected, so more frequent filter changes. Whether this is an issue with the Racors or not, I have no idea, not being familiar with them. But if you want maximum system efficiency, maximum filter loading capacity, and longest interval between changeouts, discharge filtration is the way to go. Or...just use more *wind*, and all this diesel stuff is moot :-) Keith Hughes |
Fuel Polishing again.
Well since you dont seem to know that a centrifuge is typically used
for ABOVE 10% solids removal and polishing filtration is typically used for 0.05% solids removal .... then I guess that I WONT trust you. 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 |
Fuel Polishing again.
Well since you dont seem to know that a centrifuge is typically used
for ABOVE 10% solids removal and polishing filtration is typically used for 0.05% solids removal .... then I guess that I WONT trust you. 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 |
Fuel Polishing again.
Ask the centrifuge manufacturer whats the reduction efficiency (per minute) vs. a dead end filter at 98-100% efficiency. On a per gram basis what is the cost (including initial capital cost) be tween filtration and centrifugation? Ask the centrifuge manufacturer how long the electric cord needs to be when you're out at sea. Ask what the rebuild charge is for the disks when they become misaligned or wear out.... ditto seals. Ask when do you shut down the centifuge when you know that the particle distribution is what you want to obtain .... with out accessory instrumentation and the knowledge of it proper usage. Do you have ANY idea? Now Mr. Know it ALL - go to the Alpha Laval site and look at the recommendations carefully .... and see the differences listed there for the selection criteria between filtration and centrifugation ..... wow! whaddaya know the centrifuge recommendationis for 10% solids and above. Tell me this ONE answer..... how long do you have to centrifuge fuel oil to get to 2uM particle levels? If you cant answer this, then you have NO idea of the purpose of a centrifuge, the reduction possible, nor the applicability. In article t, Rick wrote: 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.
Ask the centrifuge manufacturer whats the reduction efficiency (per minute) vs. a dead end filter at 98-100% efficiency. On a per gram basis what is the cost (including initial capital cost) be tween filtration and centrifugation? Ask the centrifuge manufacturer how long the electric cord needs to be when you're out at sea. Ask what the rebuild charge is for the disks when they become misaligned or wear out.... ditto seals. Ask when do you shut down the centifuge when you know that the particle distribution is what you want to obtain .... with out accessory instrumentation and the knowledge of it proper usage. Do you have ANY idea? Now Mr. Know it ALL - go to the Alpha Laval site and look at the recommendations carefully .... and see the differences listed there for the selection criteria between filtration and centrifugation ..... wow! whaddaya know the centrifuge recommendationis for 10% solids and above. Tell me this ONE answer..... how long do you have to centrifuge fuel oil to get to 2uM particle levels? If you cant answer this, then you have NO idea of the purpose of a centrifuge, the reduction possible, nor the applicability. In article t, Rick wrote: 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, all offended and whiny:
Ask the centrifuge manufacturer whats the reduction efficiency (per minute) vs. a dead end filter at 98-100% efficiency. On a per gram basis what is the cost (including initial capital cost) be tween filtration and centrifugation? Ask the centrifuge manufacturer how long the electric cord needs to be when you're out at sea. Ask what the rebuild charge is for the disks when they become misaligned or wear out.... ditto seals. Ask when do you shut down the centifuge when you know that the particle distribution is what you want to obtain .... with out accessory instrumentation and the knowledge of it proper usage. Do you have ANY idea? Yeah, I use them all the time. They work very well. Now Mr. Know it ALL - go to the Alpha Laval site and look at the recommendations carefully .... and see the differences listed there for the selection criteria between filtration and centrifugation ..... wow! whaddaya know the centrifuge recommendationis for 10% solids and above. Tell me this ONE answer..... how long do you have to centrifuge fuel oil to get to 2uM particle levels? If you cant answer this, then you have NO idea of the purpose of a centrifuge, the reduction possible, nor the applicability. I take it you don't like centrifuges. It also sounds like you have never seen or used one. Methinks you protest too much ... what is your problem anyway? Rick |
Fuel Polishing again.
Rich Hampel wrote, all offended and whiny:
Ask the centrifuge manufacturer whats the reduction efficiency (per minute) vs. a dead end filter at 98-100% efficiency. On a per gram basis what is the cost (including initial capital cost) be tween filtration and centrifugation? Ask the centrifuge manufacturer how long the electric cord needs to be when you're out at sea. Ask what the rebuild charge is for the disks when they become misaligned or wear out.... ditto seals. Ask when do you shut down the centifuge when you know that the particle distribution is what you want to obtain .... with out accessory instrumentation and the knowledge of it proper usage. Do you have ANY idea? Yeah, I use them all the time. They work very well. Now Mr. Know it ALL - go to the Alpha Laval site and look at the recommendations carefully .... and see the differences listed there for the selection criteria between filtration and centrifugation ..... wow! whaddaya know the centrifuge recommendationis for 10% solids and above. Tell me this ONE answer..... how long do you have to centrifuge fuel oil to get to 2uM particle levels? If you cant answer this, then you have NO idea of the purpose of a centrifuge, the reduction possible, nor the applicability. I take it you don't like centrifuges. It also sounds like you have never seen or used one. Methinks you protest too much ... what is your problem anyway? Rick |
Fuel Polishing again.
Rich Hampel wrote:
Well since you dont seem to know that a centrifuge is typically used for ABOVE 10% solids removal and polishing filtration is typically used for 0.05% solids removal .... then I guess that I WONT trust you. I am shattered. Rick |
Fuel Polishing again.
Rich Hampel wrote:
Well since you dont seem to know that a centrifuge is typically used for ABOVE 10% solids removal and polishing filtration is typically used for 0.05% solids removal .... then I guess that I WONT trust you. I am shattered. Rick |
Fuel Polishing again.
On Sat, 10 Jan 2004 12:53:52 -0700, Keith Hughes
wrote: Steven Shelikoff wrote: ...filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? It's often a function of system and pump design. For e.g., when using a centrifugal pump (or liquid ring, and sometimes vane), the inlet is typically sized larger than the outlet. The result is higher fluid velocity on the outlet side versus the 'suction' side. Higher velocity, higher impact pressure, often resulting in better particulate retention. Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? Additionally, all pump curves I've seen are, to some degree, more dependent on suction head than discharge head, and cavitation becomes an issue (i.e. efficiency drops more rapidly for loss of head on the suction side than for increase in head on the discharge side). Thus, when the filter begins to clog, you not only lose flowrate due to loop pressure drop increasing, you lose pump *efficiency* as well, exacerbating the problem. The result is, typically, less allowable filter loading before the system performance is affected, so more frequent filter changes. Basically, the above is saying that the pump can push better than it cal pull. That I agree with. But if it can pull well enough to maintain enough pressure differential across the filter up to the point where you would want to change the filter anyway, it becomes a non-issue. Especially if you're not as worried about filter element replacement costs as you are about other aspects of the system such as polishing ability and safety. Whether this is an issue with the Racors or not, I have no idea, not being familiar with them. But if you want maximum system efficiency, maximum filter loading capacity, and longest interval between changeouts, discharge filtration is the way to go. And if I want maximum life out of the pump (it's always seeing clean fuel), filtration capability (the pump isn't emulsifying the fuel just before it gets to the filter) and safety (a leak will shut the system down rather than pump fuel into the bilge) then I'd go the other way. You pick the parameters you want to maximize and go with it. Or...just use more *wind*, and all this diesel stuff is moot :-) Yup. Steve |
Fuel Polishing again.
On Sat, 10 Jan 2004 12:53:52 -0700, Keith Hughes
wrote: Steven Shelikoff wrote: ...filter media, by definition we are ignoring the case. My question is why does it matter strictly to the performance of the filter media whether fuel is being pushed through by a pump or pushed through by atmospheric pressure? It's often a function of system and pump design. For e.g., when using a centrifugal pump (or liquid ring, and sometimes vane), the inlet is typically sized larger than the outlet. The result is higher fluid velocity on the outlet side versus the 'suction' side. Higher velocity, higher impact pressure, often resulting in better particulate retention. Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? Additionally, all pump curves I've seen are, to some degree, more dependent on suction head than discharge head, and cavitation becomes an issue (i.e. efficiency drops more rapidly for loss of head on the suction side than for increase in head on the discharge side). Thus, when the filter begins to clog, you not only lose flowrate due to loop pressure drop increasing, you lose pump *efficiency* as well, exacerbating the problem. The result is, typically, less allowable filter loading before the system performance is affected, so more frequent filter changes. Basically, the above is saying that the pump can push better than it cal pull. That I agree with. But if it can pull well enough to maintain enough pressure differential across the filter up to the point where you would want to change the filter anyway, it becomes a non-issue. Especially if you're not as worried about filter element replacement costs as you are about other aspects of the system such as polishing ability and safety. Whether this is an issue with the Racors or not, I have no idea, not being familiar with them. But if you want maximum system efficiency, maximum filter loading capacity, and longest interval between changeouts, discharge filtration is the way to go. And if I want maximum life out of the pump (it's always seeing clean fuel), filtration capability (the pump isn't emulsifying the fuel just before it gets to the filter) and safety (a leak will shut the system down rather than pump fuel into the bilge) then I'd go the other way. You pick the parameters you want to maximize and go with it. Or...just use more *wind*, and all this diesel stuff is moot :-) Yup. Steve |
Fuel Polishing again.
Steven Shelikoff wrote:
Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. You pick the parameters you want to maximize and go with it. So true... Keith Hughes |
Fuel Polishing again.
Steven Shelikoff wrote:
Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. You pick the parameters you want to maximize and go with it. So true... Keith Hughes |
Fuel Polishing again.
On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes
wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes
wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
I'm building my system with one filter (10uM) in front of the pump and
one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
I'm building my system with one filter (10uM) in front of the pump and
one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
On Sun, 11 Jan 2004 10:52:16 -0500, "Doug Dotson"
wrote: I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. The valves would have letters stamped on it for what they're rated for. I forget the order of the initials but they're ones for gas, water, oil, air, etc. If it's rated for oil (has an O in the rating) it should work fine for diesel fuel. Steve |
Fuel Polishing again.
On Sun, 11 Jan 2004 10:52:16 -0500, "Doug Dotson"
wrote: I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. The valves would have letters stamped on it for what they're rated for. I forget the order of the initials but they're ones for gas, water, oil, air, etc. If it's rated for oil (has an O in the rating) it should work fine for diesel fuel. Steve |
Fuel Polishing again.
Make sure the Apollo valves are specifically rated for fuel. Something
about the seats is different. I noticed this when I was building my polishing system. "Doug Dotson" wrote in message ... I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
Make sure the Apollo valves are specifically rated for fuel. Something
about the seats is different. I noticed this when I was building my polishing system. "Doug Dotson" wrote in message ... I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
I decide to go with the Tempo type. Already had one and picked
up a 3-way last spring at the used boat parts place in St. Augustine. Assembled the filters and most of the plumbing today, pump should arrive on Tuesday ($81 brand new on eBay). I;ll take a digipic when done for anyone that is interested in seeing it. Doug s/v Callista "Keith" wrote in message ... Make sure the Apollo valves are specifically rated for fuel. Something about the seats is different. I noticed this when I was building my polishing system. "Doug Dotson" wrote in message ... I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
I decide to go with the Tempo type. Already had one and picked
up a 3-way last spring at the used boat parts place in St. Augustine. Assembled the filters and most of the plumbing today, pump should arrive on Tuesday ($81 brand new on eBay). I;ll take a digipic when done for anyone that is interested in seeing it. Doug s/v Callista "Keith" wrote in message ... Make sure the Apollo valves are specifically rated for fuel. Something about the seats is different. I noticed this when I was building my polishing system. "Doug Dotson" wrote in message ... I'm building my system with one filter (10uM) in front of the pump and one (1uM) after the pump. That way the pump is protected. Incidently, are the regular Apollo ball valves available at West Marine suitable for diesel? I have noticed Apollo valves in a number of the pics of systems folks have sent me but not sure if they are the typical ones. I had planned on using the small Tempo valves that are specifically made for fuel and are alot smaller. Doug s/v Callista "Steven Shelikoff" wrote in message ... On Sat, 10 Jan 2004 16:29:32 -0700, Keith Hughes wrote: Steven Shelikoff wrote: Sounds like we have to limit this further. Ok, I'll limit it to the typical filter, like a Racor fuel filter, with a typical pump, like the Walbro, with the pump either before or after the Racor attached to it by at least a few feet of hose and in both cases, a 3 psi difference between the outlet and inlet. How would you explain a difference in the performance of the filter media between the pump pushing or pulling the fuel? I did not claim there *is* a difference. As long as the DP is the same, and fluid velocity is the same, there should be no appreciable difference. I mean, if you continue to "limit this further" such that all pneumatic parameters are identical, operating in a steady state condition, then of course there's no difference between suction and pressure filtration. There can't be, QED. Exactly my point. I don't see how there could be a difference between pushing and pulling "all else being equal". But Rich keeps saying there is a difference and that the difference is unexplainable and is just waiting for a doctoral thesis in filterology to explain it. The point I was making is that in real world applications, parameters will not be identical, and the system is not steady state. So you have to factor in the overall system design (pump curves, filter cartridge design, flow rates, velocities, etc.) to determine if there may be an impact, since the filter does *not* operate independently of the overall system. For your basic 'rock-n-alligator' filters, I would not expect any differences. And if I want maximum life out of the pump You put a strainer in front of it. The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. You pick the parameters you want to maximize and go with it. So true... Steve |
Fuel Polishing again.
Jere Lull wrote:
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. Racor rates the plastic bowls for vacuum and up to 15 psig. Rick |
Fuel Polishing again.
Jere Lull wrote:
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. Racor rates the plastic bowls for vacuum and up to 15 psig. Rick |
Fuel Polishing again.
Steven Shelikoff wrote:
The pump already comes with a strainer. But it's a royal PITA to replace and really only gets out the largest of crud. For a "strainer" to be effective, it's just another filtration stage and we're back to sucking fuel through a filter rather than pushing it through. Install a "basket strainer" before the pump suction. It is a coarse screen that will not normally decrease the suction head but will keep small animals, rags, and rust flakes out of the suction filter and/or pump. They are very easy and quick to clean. A normal system on boats other than tiny sailboats uses, in order of flow; a coarse strainer, a set of Racors or equivalent, the service pump, then whatever filtration is mounted on and/or supplied or recommended by the engine manufacturer. Those upstream filters are normally canned type and operate under service pump pressure. If the system is supposed to serve as a polishing system as well I would provide for a bypass system to direct fuel from the service pump to a set of larger and finer filters which are plumbed back to the source tank. I am getting a bit curious at why there is so much controversy in such a common and ordinary installation? The purpose of any of these systems, I repeat, is not to conserve or extend filter life. It is to clean the fuel as effectively as possible. Rick |
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