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Author Topic: Injector preheaters, making your own  (Read 20129 times)

rcavictim

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Re: Injector preheaters, making your own
« Reply #15 on: October 30, 2006, 04:58:31 AM »
I guess my challenge now is to find a source of suitable ceramic beads.  Anyone have any ideas?
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buickanddeere

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Re: Injector preheaters, making your own
« Reply #16 on: October 30, 2006, 05:17:54 AM »
  How about a heat exchanger using exhaust thermnal energy? It would even be possible to send some heated fuel back via a return line to the supply tank. This would improve filtration and col/cold weather flow from storage.

Guy_Incognito

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Re: Injector preheaters, making your own
« Reply #17 on: October 30, 2006, 05:24:37 AM »
Try :

http://www.saxonburgceramics.com/ceramic-insulators/ball-socket.html

or

http://www.du-co.com/standard/ball.php

Hmmm. In the same city? Makes me wonder if they're in cahoots.

But I'd probably get some from RS components, as they're pretty good on supply/delivery times.
http://rswww.com/cgi-bin/bv/rswww/searchBrowseAction.do?obs=sObs&name=SiteStandard&No=0&N=0&Ntk=I18NAll&Ntt=fishspine
(If that URL's mangled, search for 'fishspine' on the RS components site.)

rcavictim

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Re: Injector preheaters, making your own
« Reply #18 on: October 30, 2006, 05:29:29 AM »

     Re: Injector preheaters, making your own
« Reply #16 on: October 29, 2006, 09:17:54 pm »
   Reply with quote
  How about a heat exchanger using exhaust thermnal energy? It would even be possible to send some heated fuel back via a return line to the supply tank. This would improve filtration and col/cold weather flow from storage.


Buick,

If you can successfully wrap a section of exhaust pipe around the fuel injector that allows the injector to be serviced when required please do so and send us pictures of how you did it.

For me a injector heater that is practical, effective and easy to service is more important than the 25-50 watts of electrricity it will rob from the output of the plant.
« Last Edit: October 30, 2006, 11:49:52 PM by rcavictim »
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

dkwflight

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Re: Injector preheaters, making your own
« Reply #19 on: October 30, 2006, 11:16:31 PM »
here is their reply

Dennis,

 

There are many factors that will affect the amount of heat you will see in this type of application.  The cable’s output is directly affected by its environment.  To estimate the heat, you will need the following information:

 

Insulation type and thickness- friction tape is not a traditional insulation, would need K Factor and thickness

Line size, outer diameter

Minimum ambient temperature

Wind speed

Is product flowing or non-flowing- if flowing, you will need additional information such as flow rate, specific heat, mass, incoming temps, etc.

 

To evaluate this yourself, you can download our design software from the website and input your variables.

 

Best regards,

 

Nelson Heat Trace

 


Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

dkwflight

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Re: Injector preheaters, making your own
« Reply #20 on: October 30, 2006, 11:20:12 PM »
Hi
The ceramic bead idea has merit. I was thinking a light dimmer, with enough capacity, would control the temps OK.
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

rcavictim

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Re: Injector preheaters, making your own
« Reply #21 on: October 30, 2006, 11:56:52 PM »
Hi
The ceramic bead idea has merit. I was thinking a light dimmer, with enough capacity, would control the temps OK.
Dennis

The light dimmer will work to adjust the heat OK but I wouldn`t operate such a heater in intimate contact with a grounded engine block without some form of transformer mains isolation for shock and fire protection.  You could use the dimmer with a 120 volt to 120 volt line isolation xfmer that was rated at the wattage required.  The dimmer would go after the xfmer on the heater element side of the xfmer.  When I suggested a DIY ceramic bead heater element in the earlier post you will note I suggested ther use of an isolating xfmer.  With a step down xfmer of the appropriate voltage for the application the dimmer or variac, etc. could be eliminated entirely.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

Andre Blanchard

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Re: Injector preheaters, making your own
« Reply #22 on: October 31, 2006, 12:13:57 AM »
With a step down xfmer of the appropriate voltage for the application the dimmer or variac, etc. could be eliminated entirely.

With the appropriate voltage out of the transformer you could also just use the steel injector line as the heater element.
______________
Andre' B

rcavictim

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Re: Injector preheaters, making your own
« Reply #23 on: October 31, 2006, 12:25:21 AM »
With a step down xfmer of the appropriate voltage for the application the dimmer or variac, etc. could be eliminated entirely.

With the appropriate voltage out of the transformer you could also just use the steel injector line as the heater element.


If you just wanted to heat the line that would work very well.  In my case I wish to concentrate heat on the injector itself.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

SCOTT

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Re: Injector preheaters, making your own
« Reply #24 on: October 31, 2006, 02:07:22 AM »
Here is what I use for preheating vo:
Item #3641k23 page 473 at Mcmaster.

I wrapped the 3ft section of wire around ¼” copper tubing that I used to replace the stock steel line.  As you can see from the picture below I added a temp probe using a brass “T” close to the of injection coupling.  I was able to get temps as high as 250f and probably could have gone higher if I had not unplugged the heater



That is all fine and good, but I don’t want to baby-sit this thing, so I am going to add a bimetal thermal switch which will be configured as normally closed open on rise at 250f.  The switch should arrive by next week. 

High pressure line:
I am not sure what kind of pressure the pump creates, and I only used copper because it was easy to work with for this initial test.  I had intended on using brake line as the injector line, it has pretty good flex and can withstand higher pressures than the copper.   I have tested the copper arrangement for a few weeks and one drawback is the amount of time it takes to purge the system of Veg oil after switching back to diesel.  As you can see in the picture below the ID of the copper is much greater than the original steel line, the steel is <2mm and the copper is around 5mm.



The wire above is with the shielding pulled back.


The copper conducts better but the steel is stronger and allows for a quicker changeover, I will use the steel.  Another advantage of the steel is that the thickness of the walls allows for some degree of heat storage, it is like a mini heat sink.  This becomes important when the load increases, the temp will not drop as quickly as with the thin walled copper.  Going along with the heat sink theme the new version I am building will have an area of increased mass to allow for more heat storage. It is in some ways analogous to the flywheel on the lister itself, they store kinetic energy, the increased mass will store the heat, helping to lessen internal veg oil temp swings.  See below



That piece of steel is 1 ¼” thick x 1 ¼” wide and about 2” long it weighs about 1lb.  The hole in the picture will be taped ¼” NPT to accept the temp switch; there is another hole on the side for the temp probe, which is just an automotive temp gage.  The heat rope will be countersunk into the block and the edges will be rounded, I may add conductive putty but I don’t think it will be needed.  The entire line and steel piece will be insulated with ceramic insulation from Mcmaster

One last note, it is important to cover the line from the pump on up to the injector, the flywheels create a lot of air movement, simply holding a piece of cardboard under the line allowed the fluid temp to rise at a faster rate. 

When the next version is done I will post some pics and some performance data.

Scott
« Last Edit: October 31, 2006, 02:10:14 AM by SCOTT »
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Geno

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Re: Injector preheaters, making your own
« Reply #25 on: October 31, 2006, 12:46:17 PM »
Here is what I use for preheating vo:
Item #3641k23 page 473 at Mcmaster.
I wrapped the 3ft section of wire around ¼” copper tubing that I used to replace the stock steel line.
Scott

Good info. Thats the stuff I was thinking about trying after reading Dennis's experiment. 3' of that stuff equals 125 watts. No wonder it got so hot. Based on your findings I'll probably try 6" (25w) or a foot (50w) wrapped directly around the injector and wrapped in some high temp tape. When up to temp my injector housing shoots at 160-170°F I don't think I'll need more than a few watts to get it up to 250°F
Thanks, Geno

buickanddeere

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Re: Injector preheaters, making your own
« Reply #26 on: October 31, 2006, 04:33:35 PM »
  "If you can successfully wrap a section of exhaust pipe around the fuel injector that allows the injector to be serviced when required please do so and send us pictures of how you did it."

  I was talking about pre-heating the fuel just prior to the injection pump. It's not too difficuilt to make a double wall hx for the exhaust stack. Or even just loop the line in a coil in close proximity to the exhaust stack. My Deere tractor has a couple of loops from each of the injector return lines between each leg of the exhaust manifold. The fuel line returning to the tank is plenty warm to hang onto.
  Exhaust heat system is easier to control with a return line to the fuel tank. Keeping the alternate fuel warm in the tank and through the filter never hurt either. Waxed up or jellyed fuel never flows very well through a tank/line/pump/filter or what ever. Alternate fuel more so than #2 diesel oil. 
  Starting on diesel and swapping to atlernate fuel once temps have been achieved is the usual method. Insulating the line between the injection pump and the injector will keep the fuel hot. On a 210F coolant temp engine the injector should be hot enough  it's at least not cooling down the fuel.   
  Of course with the hotter, less dense and light viscosity fuel. Injection delievery will have to be increased slightly to maintain full HP.
  This system also keeps the clutter away from the high pressure pipe work.

gpkull

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Re: Injector preheaters, making your own
« Reply #27 on: November 01, 2006, 01:18:17 AM »
heaters for your injector lines can be purchased pretty much dirt cheap. 12volt 12bucks each have not priced 120volt but dont need to. yes preheat the golden or black gold to the ip but the line heater after the ip heats to way higher than the ip can stand and the inj loves it . can heat till your juice cooks or cokes in the line the hotter the more viscuos = the better atomization = the cleaner burn less carbon . i would not waste my time with beads and such. thats me and for what its worth thats my two pennys

Geno

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Re: Injector preheaters, making your own
« Reply #28 on: November 01, 2006, 11:37:40 AM »
Here is what I use for preheating vo:
Item #3641k23 page 473 at Mcmaster.

Hi Scott, can that heat tape be cut shorter to give less wattage? I'd like to buy a couple one foot pieces, one for the injector and one for the IP and would like to customize the output for each application. The price is about the same and I don't want to come up short with 6" pieces.

Thanks, Geno

SCOTT

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Re: Injector preheaters, making your own
« Reply #29 on: November 01, 2006, 01:43:39 PM »
Geno
There is nothing specific in the description that says they can be shortened, but then again there is nothing that says they cant.  In practice they can be cut to shorter lengths.  I know this only because I was a bit to aggressive unwrapping the wire from the injector line.  The wire lead separated from the thin coiled heating element, I just cut some of the core material away and re crimped the lead wire back on.  The element works fine, using a Kill-o-watt meter, my 36” wire draws about 100watts, so based on the mcmaster numbers I cut off 25watts worth of element.

You may consider adding a thermal temp switch, they can be had for about $30 and they will do a good job regulating the temp.  I should have one operational in about a week, mine is a probe that will be in contact with the actual fuel.  I think that a surface mounted thermal temp switch would also do a pretty good job; you would just have to raise the set point a little because you are not measuring the actual fuel temp.  The surface mounted switch has the advantage of allowing you to keep the fuel line intact, and makes for a less complicated install.

Scott
net metering with a 6/1 in Connecticut
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